Path seperator cleanup

Single-Header/dn_single_header.h

@@ -1,4 +1,4 @@
-// Generated by the DN single header generator 2026-07-19 16:12:36
+// Generated by the DN single header generator 2026-07-31 22:40:42
 
 #if !defined(DN_H)
 #define DN_H
@@ -302,6 +302,7 @@
 // NOTE: Platform identification
 #if !defined(DN_PLATFORM_EMSCRIPTEN) && \
     !defined(DN_PLATFORM_POSIX) &&      \
+    !defined(DN_PLATFORM_ARM64) &&      \
     !defined(DN_PLATFORM_WIN32)
   #if defined(__aarch64__) || defined(_M_ARM64)
     #define DN_PLATFORM_ARM64
@@ -1504,6 +1505,25 @@ enum DN_Str8BuilderAdd
   DN_Str8BuilderAdd_Prepend,
 };
 
+#if !defined(DN_OsPathSeperator)
+  #if defined(DN_PLATFORM_WIN32)
+    #define DN_OsPathSeperator "\\"
+  #else
+    #define DN_OsPathSeperator "/"
+  #endif
+  #define DN_OsPathSeperatorStr8 DN_Str8Lit(DN_OsPathSeperator)
+#endif
+
+typedef struct DN_Path DN_Path;
+struct DN_Path
+{
+  bool         has_prefix_path_seperator;
+  DN_Str8Link *head;
+  DN_Str8Link *tail;
+  DN_USize     string_size;
+  DN_U16       links_size;
+};
+
 typedef DN_U32 DN_AgeUnit;
 enum DN_AgeUnit_
 {
@@ -4227,7 +4247,6 @@ enum DN_OSFileRotateFlags_
   DN_OSFileRotateFlags_KeepBaseFile = 1 << 0,
 };
 
-
 enum DN_OSPathInfoType
 {
   DN_OSPathInfoType_Unknown,
@@ -4286,34 +4305,6 @@ enum DN_OSFileAccess_
   DN_OSFileAccess_All        = DN_OSFileAccess_ReadWrite | DN_OSFileAccess_Execute | DN_OSFileAccess_AppendOnly,
 };
 
-// NOTE: DN_OSPath
-#if !defined(DN_OSPathSeparator)
-  #if defined(DN_PLATFORM_WIN32)
-    #define DN_OSPathSeparator "\\"
-  #else
-    #define DN_OSPathSeparator "/"
-  #endif
-  #define DN_OSPathSeparatorStr8 DN_Str8Lit(DN_OSPathSeparator)
-#endif
-
-typedef struct DN_OSPathLink DN_OSPathLink;
-struct DN_OSPathLink
-{
-  DN_Str8        string;
-  DN_OSPathLink *next;
-  DN_OSPathLink *prev;
-};
-
-typedef struct DN_OSPath DN_OSPath;
-struct DN_OSPath
-{
-  bool           has_prefix_path_separator;
-  DN_OSPathLink *head;
-  DN_OSPathLink *tail;
-  DN_USize       string_size;
-  DN_U16         links_size;
-};
-
 typedef DN_U32 DN_OSExecFlags;
 enum DN_OSExecFlags_
 {
@@ -5028,7 +5019,7 @@ DN_API void                     DN_Str8x512AppendFmtV
 DN_API void                     DN_Str8x1024AppendFmt                                  (DN_Str8x1024 *str, DN_FMT_ATTRIB char const *fmt, ...);
 DN_API void                     DN_Str8x1024AppendFmtV                                 (DN_Str8x1024 *str, DN_FMT_ATTRIB char const *fmt, va_list args);
 
-DN_API DN_Str8x32               DN_Str8x32FromU64                                      (DN_U64 val, char separator);
+DN_API DN_Str8x32               DN_Str8x32FromU64                                      (DN_U64 val, char seperator);
 DN_API bool                     DN_Str8Is                                              (DN_Str8 string, DN_Str8IsFlags flags);
 DN_API char *                   DN_Str8End                                             (DN_Str8 string);
 DN_API DN_Str8                  DN_Str8Subset                                          (DN_Str8 string, DN_USize offset, DN_USize count);
@@ -5104,13 +5095,13 @@ DN_API DN_USize                 DN_Str8SplitAVX512F
 DN_API DN_Str8Slice             DN_Str8SplitAllocAVX512F                               (DN_Arena *arena, DN_Str8 string, DN_Str8 delimiter, DN_Str8SplitFlags flags);
 #endif
 
-DN_API DN_Str8                  DN_Str8SliceRender                                     (DN_Str8Slice array, DN_Str8 separator, DN_Arena *arena);
+DN_API DN_Str8                  DN_Str8SliceRender                                     (DN_Str8Slice array, DN_Str8 seperator, DN_Arena *arena);
 DN_API DN_Str8                  DN_Str8RenderSpaceSep                                  (DN_Str8Slice array, DN_Arena *arena);
 DN_API int                      DN_Str8CompareNatural                                  (DN_Str8 lhs, DN_Str8 rhs, DN_Str8EqCase eq_case);
 DN_API int                      DN_Str8CompareLexicographic                            (DN_Str8 lhs, DN_Str8 rhs, DN_Str8EqCase eq_case);
 
 DN_API bool                     DN_Str16Eq                                             (DN_Str16 lhs, DN_Str16 rhs);
-DN_API DN_Str16                 DN_Str16SliceRender                                    (DN_Str16Slice array, DN_Str16 separator, DN_Arena *arena);
+DN_API DN_Str16                 DN_Str16SliceRender                                    (DN_Str16Slice array, DN_Str16 seperator, DN_Arena *arena);
 DN_API DN_Str16                 DN_Str16RenderSpaceSep                                 (DN_Str16Slice array, DN_Arena *arena);
 
 DN_API DN_Str8Builder           DN_Str8BuilderFromArena                                (DN_Arena *arena);
@@ -5146,6 +5137,18 @@ DN_API DN_Str8                  DN_Str8FromStr8BuilderArena
 DN_API DN_Str8                  DN_Str8FromStr8BuilderDelimitAllocator                 (DN_Str8Builder const *builder, DN_Str8 delimiter, DN_Allocator allocator);
 DN_API DN_Str8                  DN_Str8FromStr8BuilderDelimitArena                     (DN_Str8Builder const *builder, DN_Str8 delimiter, DN_Arena *arena);
 
+DN_API bool                     DN_PathAddRef                                          (DN_Path *path, DN_Str8 add, DN_Arena *arena);
+DN_API bool                     DN_PathAdd                                             (DN_Path *path, DN_Str8 add, DN_Arena *arena);
+DN_API bool                     DN_PathAddF                                            (DN_Path *path, DN_FMT_ATTRIB char const *fmt, ...);
+DN_API bool                     DN_PathPop                                             (DN_Path *path);
+DN_API DN_Str8                  DN_Str8FromPath                                        (DN_Path const *path, DN_Str8 path_seperator, DN_Allocator allocator);
+DN_API DN_Str8                  DN_Str8FmtPathVArena                                   (DN_Str8 path_seperator, DN_Arena *arena, char const *fmt, va_list args);
+DN_API DN_Str8                  DN_Str8FmtPathArena                                    (DN_Str8 path_seperator, DN_Arena *arena, DN_FMT_ATTRIB char const *fmt, ...);
+DN_API DN_Str8                  DN_Str8FmtPathVPool                                    (DN_Str8 path_seperator, DN_Pool  *pool,  char const *fmt, va_list args);
+DN_API DN_Str8                  DN_Str8FmtPathPool                                     (DN_Str8 path_seperator, DN_Pool  *pool,  DN_FMT_ATTRIB char const *fmt, ...);
+DN_API DN_Str8                  DN_Str8FmtOsPathArena                                  (DN_Arena *arena, DN_FMT_ATTRIB char const *fmt, ...);
+DN_API DN_Str8                  DN_Str8FmtOsPathPool                                   (DN_Pool  *pool,  DN_FMT_ATTRIB char const *fmt, ...);
+
 DN_API int                      DN_UTF8Encode                                          (DN_U8 utf8[4], DN_U32 codepoint);
 DN_API int                      DN_UTF16Encode                                         (DN_U16 utf16[2], DN_U32 codepoint);
 DN_API DN_UTF8DecodeResult      DN_UTF8Decode                                          (DN_Str8 stream);
@@ -5249,7 +5252,14 @@ DN_API void                     DN_ProfilerFmtToStdout
 DN_API DN_F64                   DN_ProfilerSecFromTsc                                  (DN_Profiler *profiler, DN_U64 duration_tsc);
 DN_API DN_F64                   DN_ProfilerMsFromTsc                                   (DN_Profiler *profiler, DN_U64 duration_tsc);
 
-DN_API void                     DN_QSort                                               (void *array, DN_USize array_size, DN_USize elem_size, void *user_context, DN_QSortCompareFunc *compare);
+DN_API void                     DN_QSort_                                              (void *array, DN_USize array_size, DN_USize elem_size, void *user_context, DN_QSortCompareFunc *compare);
+#if defined(__cplusplus)
+template <typename T> void      DN_QSortT                                              (T *array, DN_USize array_size, void *user_context, DN_QSortCompareFunc *compare);
+#define                         DN_QSort(array, array_size, user_context, compare)     DN_QSortT(array, array_size, user_context, compare)
+#else
+#define                         DN_QSort(array, array_size, user_context, compare)     DN_QSort_(array, array_size, sizeof(*array), user_context, compare)
+#endif
+
 DN_API bool                     DN_QSortCompareStr8NaturalAsc                          (void const* lhs, void const *rhs, void *user_context);
 DN_API bool                     DN_QSortCompareStr8NaturalDesc                         (void const* lhs, void const *rhs, void *user_context);
 DN_API bool                     DN_QSortCompareStr8LexicographicAsc                    (void const* lhs, void const *rhs, void *user_context);
@@ -5278,12 +5288,12 @@ DN_API DN_F32                   DN_Pcg32NextF32
 DN_API DN_F64                   DN_Pcg32NextF64                                        (DN_Pcg32 *rng);
 DN_API void                     DN_Pcg32Advance                                        (DN_Pcg32 *rng, DN_U64 delta);
 
-#if !defined(DN_Fnv1a32_SEED)
+#if !defined(DN_FNV1A32_SEED)
-  #define DN_Fnv1a32_SEED 2166136261U
+  #define DN_FNV1A32_SEED 2166136261U
 #endif
 
-#if !defined(DN_Fnv1a64_SEED)
+#if !defined(DN_FNV1A64_SEED)
-  #define DN_Fnv1a64_SEED 14695981039346656037ULL
+  #define DN_FNV1A64_SEED 14695981039346656037ULL
 #endif
 
 DN_API DN_U32                   DN_Fnv1aHashU32FromBytes                               (void const *bytes, DN_USize count, DN_U32 seed);
@@ -5429,10 +5439,16 @@ DN_API DN_V2U16&               operator/=
 DN_API DN_V2U16&               operator-=                                              (DN_V2U16& lhs, DN_V2U16 rhs);
 DN_API DN_V2U16&               operator+=                                              (DN_V2U16& lhs, DN_V2U16 rhs);
 
-#define                        DN_V2U32Zero                                            DN_Literal(DN_V2U32){{(DN_U32)(0), (DN_U32)(0)}}
+// NOTE: DN_V2F32
-#define                        DN_V2U32One                                             DN_Literal(DN_V2U32){{(DN_U32)(1), (DN_U32)(1)}}
+// API
-#define                        DN_V2U32From1N(x)                                       DN_Literal(DN_V2U32){{(DN_U32)(x), (DN_U32)(x)}}
+//   DN_V2F32Rotate
-#define                        DN_V2U32From2N(x, y)                                    DN_Literal(DN_V2U32){{(DN_U32)(x), (DN_U32)(y)}}
+//     Rotate a vector using the precomputed cosine and sine value of the angle (e.g.
+//     `cos_a => cos(your_angle * 2.f * DN_PiF32)` and `sin_a => sinf(your_angle * 2.f * DN_PiF32)`)
+#define                        DN_V2U32Zero                                            DN_Literal(DN_V2U32){{(DN_U32)(0),    (DN_U32)(0)}}
+#define                        DN_V2U32One                                             DN_Literal(DN_V2U32){{(DN_U32)(1),    (DN_U32)(1)}}
+#define                        DN_V2U32From1N(x)                                       DN_Literal(DN_V2U32){{(DN_U32)(x),    (DN_U32)(x)}}
+#define                        DN_V2U32From2N(x, y)                                    DN_Literal(DN_V2U32){{(DN_U32)(x),    (DN_U32)(y)}}
+#define                        DN_V2U32FromV2(v2)                                      DN_Literal(DN_V2U32){{(DN_U32)(v2.x), (DN_U32)(v2.y)}}
 
 #define                        DN_V2F32Zero                                            DN_Literal(DN_V2F32){{(DN_F32)(0),    (DN_F32)(0)}}
 #define                        DN_V2F32One                                             DN_Literal(DN_V2F32){{(DN_F32)(1),    (DN_F32)(1)}}
@@ -5441,6 +5457,7 @@ DN_API DN_V2U16&               operator+=
 #define                        DN_V2F32FromV2(xy)                                      DN_Literal(DN_V2F32){{(DN_F32)(xy).x, (DN_F32)(xy).y}}
 
 DN_API DN_V2F32                DN_V2F32Lerp                                            (DN_V2F32 a, DN_F32 t, DN_V2F32 b);
+DN_API DN_V2F32                DN_V2F32Rotate                                          (DN_V2F32 v, DN_F32 cos_a, DN_F32 sin_a);
 
 DN_API bool                    operator!=                                              (DN_V2F32  lhs, DN_V2F32  rhs);
 DN_API bool                    operator==                                              (DN_V2F32  lhs, DN_V2F32  rhs);
@@ -5510,7 +5527,7 @@ DN_API DN_F32                  DN_V2F32Area
 
 // NOTE: Grayscale co-efficients from:
 //   https://github.com/EpicGames/UnrealEngine/blob/260bb2e1c5610b31c63a36206eedd289409c5f11/Engine/Source/Runtime/Core/Private/Math/Color.cpp#L304
-DN_V3F32 static const          DN_V3F32_Rgb_LUMINANCE = DN_V3F32From3N(0.3f, 0.59f, 0.11f);
+DN_V3F32 static const          DN_V3F32_RGB_LUMINANCE = DN_V3F32From3N(0.3f, 0.59f, 0.11f);
 
 DN_API bool                    operator==                                              (DN_V3F32  lhs, DN_V3F32  rhs);
 DN_API bool                    operator!=                                              (DN_V3F32  lhs, DN_V3F32  rhs);
@@ -6526,8 +6543,8 @@ DN_API void *                    DN_OS_MemAlloc                               (D
 DN_API void                      DN_OS_MemDealloc                             (void *ptr);
 
 DN_API DN_Date                   DN_OS_DateLocalTimeNow                       ();
-DN_API DN_Str8x32                DN_OS_DateLocalTimeStr8Now                   (char date_separator = '-', char hms_separator = ':');
+DN_API DN_Str8x32                DN_OS_DateLocalTimeStr8Now                   (char date_seperator = '-', char hms_seperator = ':');
-DN_API DN_Str8x32                DN_OS_DateLocalTimeStr8                      (DN_Date time, char date_separator = '-', char hms_separator = ':');
+DN_API DN_Str8x32                DN_OS_DateLocalTimeStr8                      (DN_Date time, char date_seperator = '-', char hms_seperator = ':');
 DN_API DN_U64                    DN_OS_DateUnixTimeNs                         ();
 #define                          DN_OS_DateUnixTimeUs()                       (DN_OS_DateUnixTimeNs() / 1000)
 #define                          DN_OS_DateUnixTimeMs()                       (DN_OS_DateUnixTimeNs() / (1000 * 1000))
@@ -6626,24 +6643,6 @@ DN_API bool                      DN_OS_PathIsDir                              (D
 DN_API bool                      DN_OS_PathMakeDir                            (DN_Str8 path);
 DN_API bool                      DN_OS_PathIterateDir                         (DN_Str8 path, DN_OSDirIterator *it);
 
-DN_API bool                      DN_OS_PathAddRef                             (DN_Arena *arena, DN_OSPath *fs_path, DN_Str8 path);
-DN_API bool                      DN_OS_PathAdd                                (DN_Arena *arena, DN_OSPath *fs_path, DN_Str8 path);
-DN_API bool                      DN_OS_PathAddF                               (DN_Arena *arena, DN_OSPath *fs_path, DN_FMT_ATTRIB char const *fmt, ...);
-DN_API bool                      DN_OS_PathPop                                (DN_OSPath *fs_path);
-DN_API DN_Str8                   DN_OS_PathBuildWithSeparatorAllocator        (DN_Allocator allocator, DN_OSPath const *fs_path, DN_Str8 path_separator);
-DN_API DN_Str8                   DN_OS_PathToArena                            (DN_Arena *arena, DN_Str8 path, DN_Str8 path_separtor);
-DN_API DN_Str8                   DN_OS_PathToPool                             (DN_Pool  *pool,  DN_Str8 path, DN_Str8 path_separtor);
-DN_API DN_Str8                   DN_OS_PathToFmtArena                         (DN_Arena *arena, DN_Str8 path_separator, DN_FMT_ATTRIB char const *fmt, ...);
-DN_API DN_Str8                   DN_OS_PathToFmtPool                          (DN_Pool  *pool,  DN_Str8 path_separator, DN_FMT_ATTRIB char const *fmt, ...);
-DN_API DN_Str8                   DN_OS_PathArena                              (DN_Arena *arena, DN_Str8 path);
-DN_API DN_Str8                   DN_OS_PathPool                               (DN_Pool  *pool,  DN_Str8 path);
-DN_API DN_Str8                   DN_OS_PathFmtArena                           (DN_Arena *arena, DN_FMT_ATTRIB char const *fmt, ...);
-DN_API DN_Str8                   DN_OS_PathFmtPool                            (DN_Pool  *pool,  DN_FMT_ATTRIB char const *fmt, ...);
-
-#define                          DN_OS_PathBuildFwdSlash(allocator, fs_path)  DN_OS_PathBuildWithSeparatorAllocator(allocator, fs_path, DN_Str8Lit("/"))
-#define                          DN_OS_PathBuildBackSlash(allocator, fs_path) DN_OS_PathBuildWithSeparatorAllocator(allocator, fs_path, DN_Str8Lit("\\"))
-#define                          DN_OS_PathBuild(allocator, fs_path)          DN_OS_PathBuildWithSeparatorAllocator(allocator, fs_path, DN_OSPathSeparatorStr8)
-
 DN_API void                      DN_OS_Exit                                   (int32_t exit_code);
 DN_API DN_OSExecArgs             DN_OS_ExecArgsDefault                        ();
 DN_API DN_OSExecResult           DN_OS_ExecPump                               (DN_OSExecAsyncHandle handle, char *stdout_buffer, size_t *stdout_size, char *stderr_buffer, size_t *stderr_size, DN_U32 timeout_ms, DN_ErrSink  *err);

Source/OS/dn_os_posix.cpp

@@ -1414,25 +1414,25 @@ DN_API DN_OSPosixProcSelfStatus DN_OS_PosixProcSelfStatus()
 
     for (DN_ForItSize(line_it, DN_Str8, lines.data, lines.count)) {
       DN_Str8 line = DN_Str8TrimWhitespaceAround(*line_it.data);
-      if (DN_Str8StartsWith(line, NAME, DN_Str8EqCase_Insensitive)) {
+      if (DN_Str8StartsWithInsensitive(line, NAME)) {
         DN_Str8 str8     = DN_Str8TrimWhitespaceAround(DN_Str8Subset(line, NAME.count, line.count));
         result.name_size = DN_Min(str8.count, sizeof(result.name));
         DN_Memcpy(result.name, str8.data, result.name_size);
-      } else if (DN_Str8StartsWith(line, PID, DN_Str8EqCase_Insensitive)) {
+      } else if (DN_Str8StartsWithInsensitive(line, PID)) {
         DN_Str8          str8   = DN_Str8TrimWhitespaceAround(DN_Str8Subset(line, PID.count, line.count));
         DN_U64FromResult to_u64 = DN_U64FromStr8(str8);
         result.pid              = to_u64.value;
         DN_Assert(to_u64.success);
-      } else if (DN_Str8StartsWith(line, VM_SIZE, DN_Str8EqCase_Insensitive)) {
+      } else if (DN_Str8StartsWithInsensitive(line, VM_SIZE)) {
         DN_Str8 size_with_kb = DN_Str8TrimWhitespaceAround(DN_Str8Subset(line, VM_SIZE.count, line.count));
-        DN_Assert(DN_Str8EndsWith(size_with_kb, DN_Str8Lit("kB")));
+        DN_Assert(DN_Str8EndsWithSensitive(size_with_kb, DN_Str8Lit("kB")));
         DN_Str8          vm_size = DN_Str8BSplit(size_with_kb, DN_Str8Lit(" ")).lhs;
         DN_U64FromResult to_u64  = DN_U64FromStr8(vm_size);
         result.vm_size           = DN_Kilobytes(to_u64.value);
         DN_Assert(to_u64.success);
-      } else if (DN_Str8StartsWith(line, VM_PEAK, DN_Str8EqCase_Insensitive)) {
+      } else if (DN_Str8StartsWithInsensitive(line, VM_PEAK)) {
         DN_Str8 size_with_kb = DN_Str8TrimWhitespaceAround(DN_Str8Subset(line, VM_PEAK.count, line.count));
-        DN_Assert(DN_Str8EndsWith(size_with_kb, DN_Str8Lit("kB")));
+        DN_Assert(DN_Str8EndsWithSensitive(size_with_kb, DN_Str8Lit("kB")));
         DN_Str8          vm_size = DN_Str8BSplit(size_with_kb, DN_Str8Lit(" ")).lhs;
         DN_U64FromResult to_u64  = DN_U64FromStr8(vm_size);
         result.vm_peak           = DN_Kilobytes(to_u64.value);

Source/OS/dn_os_w32.cpp

@@ -1,5 +1,3 @@
-#define DN_OS_W32_CPP
-
 #if defined(_CLANGD)
   #define DN_WITH_OS 1
   #include "../dn.h"
@@ -649,9 +647,9 @@ DN_API bool DN_OS_PathIterateDir(DN_Str8 path, DN_OSDirIterator *it)
       // add those characters in this branch, so overwrite the null
       // character, add the glob and re-null terminate the buffer.
       if (needs_asterisks)
-        adjusted_path = DN_OS_PathFmtArena(&scratch.arena, "%.*s*", DN_Str8PrintFmt(path));
+        adjusted_path = DN_Str8FmtOsPathArena(&scratch.arena, "%.*s*", DN_Str8PrintFmt(path));
       else
-        adjusted_path = DN_OS_PathFmtArena(&scratch.arena, "%.*s/*", DN_Str8PrintFmt(path));
+        adjusted_path = DN_Str8FmtOsPathArena(&scratch.arena, "%.*s/*", DN_Str8PrintFmt(path));
     }
 
     path16 = DN_OS_W32Str8ToStr16(&scratch.arena, adjusted_path);
@@ -867,8 +865,10 @@ DN_API DN_OSExecAsyncHandle DN_OS_ExecAsync(DN_Str8Slice cmd_line, DN_OSExecArgs
       if (it.index)
         count_req += cmd_separator.count;
 
-      if (DN_Str8Find(*it.data, DN_Str8FindFlag_Whitespace).found)
+      if (!DN_Str8StartsWithSensitive(*it.data, DN_Str8Lit("\""))) {
-        count_req += 2; // If there's whitespace, we'll quote the string for the user
+        if (DN_Str8Find(*it.data, DN_Str8FindFlag_Whitespace).found)
+          count_req += 2; // If there's whitespace, we'll quote the string for the user
+      }
       count_req += it.data->count;
     }
 
@@ -883,8 +883,11 @@ DN_API DN_OSExecAsyncHandle DN_OS_ExecAsync(DN_Str8Slice cmd_line, DN_OSExecArgs
         }
 
         // NOTE: Quote the string if needed
-        DN_Str8 str8         = *it.data;
+        DN_Str8 str8      = *it.data;
-        bool    needs_quotes = DN_Str8Find(str8, DN_Str8FindFlag_Whitespace).found;
+        bool needs_quotes = false;
+        if (!DN_Str8StartsWithSensitive(*it.data, DN_Str8Lit("\"")))
+          needs_quotes = DN_Str8Find(str8, DN_Str8FindFlag_Whitespace).found;
+
         if (needs_quotes)
           cmd.data[write_index++] = '\"';
 
@@ -932,7 +935,7 @@ DN_API DN_OSExecAsyncHandle DN_OS_ExecAsync(DN_Str8Slice cmd_line, DN_OSExecArgs
   if (DN_BitIsSet(args.flags, DN_OSExecFlags_SaveStdout)) {
     if (!CreatePipe(&stdout_read, &stdout_write, &save_std_security_attribs, /*nSize*/ 0)) {
       DN_OSW32Error win_error = DN_OS_W32LastError(&scratch.arena);
-      result.os_error_code  = win_error.code;
+      result.os_error_code    = win_error.code;
       DN_ErrSinkAppendF(
           err,
           result.os_error_code,
@@ -1001,14 +1004,23 @@ DN_API DN_OSExecAsyncHandle DN_OS_ExecAsync(DN_Str8Slice cmd_line, DN_OSExecArgs
     }
   }
 
+  // NOTE: Create a null stdin pipe so child gets EOF on read
+  // TODO: Eventually we should let the caller optionally write to stdin
+  HANDLE stdin_read  = {};
+  if (DN_BitIsSet(args.flags, DN_OSExecFlags_SaveStdout) || DN_BitIsSet(args.flags, DN_OSExecFlags_SaveStderr)) {
+    HANDLE stdin_write = {};
+    if (CreatePipe(&stdin_read, &stdin_write, &save_std_security_attribs, 0))
+      CloseHandle(stdin_write);
+  }
+
   // NOTE: Execute command
-  PROCESS_INFORMATION proc_info    = {};
+  PROCESS_INFORMATION proc_info     = {};
-  STARTUPINFOW        startup_info = {};
+  STARTUPINFOW        startup_info  = {};
-  startup_info.cb                  = sizeof(STARTUPINFOW);
+  startup_info.cb                   = sizeof(STARTUPINFOW);
-  startup_info.hStdError           = stderr_write ? stderr_write : GetStdHandle(STD_ERROR_HANDLE);
+  startup_info.hStdError            = stderr_write ? stderr_write : GetStdHandle(STD_ERROR_HANDLE);
-  startup_info.hStdOutput          = stdout_write ? stdout_write : GetStdHandle(STD_OUTPUT_HANDLE);
+  startup_info.hStdOutput           = stdout_write ? stdout_write : GetStdHandle(STD_OUTPUT_HANDLE);
-  startup_info.hStdInput           = GetStdHandle(STD_INPUT_HANDLE);
+  startup_info.hStdInput            = stdin_read ? stdin_read : GetStdHandle(STD_INPUT_HANDLE);
-  startup_info.dwFlags |= STARTF_USESTDHANDLES;
+  startup_info.dwFlags             |= STARTF_USESTDHANDLES;
   BOOL create_result = CreateProcessW(nullptr,
                                       cmd16.data,
                                       nullptr,
@@ -1019,6 +1031,9 @@ DN_API DN_OSExecAsyncHandle DN_OS_ExecAsync(DN_Str8Slice cmd_line, DN_OSExecArgs
                                       working_dir16.data,
                                       &startup_info,
                                       &proc_info);
+  if (stdin_read)
+    CloseHandle(stdin_read);
+
   if (!create_result) {
     DN_OSW32Error win_error = DN_OS_W32LastError(&scratch.arena);
     result.os_error_code  = win_error.code;

Source/dn.h

@@ -300,6 +300,7 @@
 // NOTE: Platform identification
 #if !defined(DN_PLATFORM_EMSCRIPTEN) && \
     !defined(DN_PLATFORM_POSIX) &&      \
+    !defined(DN_PLATFORM_ARM64) &&      \
     !defined(DN_PLATFORM_WIN32)
   #if defined(__aarch64__) || defined(_M_ARM64)
     #define DN_PLATFORM_ARM64
@@ -1502,6 +1503,25 @@ enum DN_Str8BuilderAdd
   DN_Str8BuilderAdd_Prepend,
 };
 
+#if !defined(DN_OsPathSeperator)
+  #if defined(DN_PLATFORM_WIN32)
+    #define DN_OsPathSeperator "\\"
+  #else
+    #define DN_OsPathSeperator "/"
+  #endif
+  #define DN_OsPathSeperatorStr8 DN_Str8Lit(DN_OsPathSeperator)
+#endif
+
+typedef struct DN_Path DN_Path;
+struct DN_Path
+{
+  bool         has_prefix_path_seperator;
+  DN_Str8Link *head;
+  DN_Str8Link *tail;
+  DN_USize     string_size;
+  DN_U16       links_size;
+};
+
 typedef DN_U32 DN_AgeUnit;
 enum DN_AgeUnit_
 {
@@ -2297,7 +2317,6 @@ enum DN_OSFileRotateFlags_
   DN_OSFileRotateFlags_KeepBaseFile = 1 << 0,
 };
 
-
 enum DN_OSPathInfoType
 {
   DN_OSPathInfoType_Unknown,
@@ -2356,34 +2375,6 @@ enum DN_OSFileAccess_
   DN_OSFileAccess_All        = DN_OSFileAccess_ReadWrite | DN_OSFileAccess_Execute | DN_OSFileAccess_AppendOnly,
 };
 
-// NOTE: DN_OSPath
-#if !defined(DN_OSPathSeparator)
-  #if defined(DN_PLATFORM_WIN32)
-    #define DN_OSPathSeparator "\\"
-  #else
-    #define DN_OSPathSeparator "/"
-  #endif
-  #define DN_OSPathSeparatorStr8 DN_Str8Lit(DN_OSPathSeparator)
-#endif
-
-typedef struct DN_OSPathLink DN_OSPathLink;
-struct DN_OSPathLink
-{
-  DN_Str8        string;
-  DN_OSPathLink *next;
-  DN_OSPathLink *prev;
-};
-
-typedef struct DN_OSPath DN_OSPath;
-struct DN_OSPath
-{
-  bool           has_prefix_path_separator;
-  DN_OSPathLink *head;
-  DN_OSPathLink *tail;
-  DN_USize       string_size;
-  DN_U16         links_size;
-};
-
 typedef DN_U32 DN_OSExecFlags;
 enum DN_OSExecFlags_
 {
@@ -3098,7 +3089,7 @@ DN_API void                     DN_Str8x512AppendFmtV
 DN_API void                     DN_Str8x1024AppendFmt                                  (DN_Str8x1024 *str, DN_FMT_ATTRIB char const *fmt, ...);
 DN_API void                     DN_Str8x1024AppendFmtV                                 (DN_Str8x1024 *str, DN_FMT_ATTRIB char const *fmt, va_list args);
 
-DN_API DN_Str8x32               DN_Str8x32FromU64                                      (DN_U64 val, char separator);
+DN_API DN_Str8x32               DN_Str8x32FromU64                                      (DN_U64 val, char seperator);
 DN_API bool                     DN_Str8Is                                              (DN_Str8 string, DN_Str8IsFlags flags);
 DN_API char *                   DN_Str8End                                             (DN_Str8 string);
 DN_API DN_Str8                  DN_Str8Subset                                          (DN_Str8 string, DN_USize offset, DN_USize count);
@@ -3174,13 +3165,13 @@ DN_API DN_USize                 DN_Str8SplitAVX512F
 DN_API DN_Str8Slice             DN_Str8SplitAllocAVX512F                               (DN_Arena *arena, DN_Str8 string, DN_Str8 delimiter, DN_Str8SplitFlags flags);
 #endif
 
-DN_API DN_Str8                  DN_Str8SliceRender                                     (DN_Str8Slice array, DN_Str8 separator, DN_Arena *arena);
+DN_API DN_Str8                  DN_Str8SliceRender                                     (DN_Str8Slice array, DN_Str8 seperator, DN_Arena *arena);
 DN_API DN_Str8                  DN_Str8RenderSpaceSep                                  (DN_Str8Slice array, DN_Arena *arena);
 DN_API int                      DN_Str8CompareNatural                                  (DN_Str8 lhs, DN_Str8 rhs, DN_Str8EqCase eq_case);
 DN_API int                      DN_Str8CompareLexicographic                            (DN_Str8 lhs, DN_Str8 rhs, DN_Str8EqCase eq_case);
 
 DN_API bool                     DN_Str16Eq                                             (DN_Str16 lhs, DN_Str16 rhs);
-DN_API DN_Str16                 DN_Str16SliceRender                                    (DN_Str16Slice array, DN_Str16 separator, DN_Arena *arena);
+DN_API DN_Str16                 DN_Str16SliceRender                                    (DN_Str16Slice array, DN_Str16 seperator, DN_Arena *arena);
 DN_API DN_Str16                 DN_Str16RenderSpaceSep                                 (DN_Str16Slice array, DN_Arena *arena);
 
 DN_API DN_Str8Builder           DN_Str8BuilderFromArena                                (DN_Arena *arena);
@@ -3216,6 +3207,18 @@ DN_API DN_Str8                  DN_Str8FromStr8BuilderArena
 DN_API DN_Str8                  DN_Str8FromStr8BuilderDelimitAllocator                 (DN_Str8Builder const *builder, DN_Str8 delimiter, DN_Allocator allocator);
 DN_API DN_Str8                  DN_Str8FromStr8BuilderDelimitArena                     (DN_Str8Builder const *builder, DN_Str8 delimiter, DN_Arena *arena);
 
+DN_API bool                     DN_PathAddRef                                          (DN_Path *path, DN_Str8 add, DN_Arena *arena);
+DN_API bool                     DN_PathAdd                                             (DN_Path *path, DN_Str8 add, DN_Arena *arena);
+DN_API bool                     DN_PathAddF                                            (DN_Path *path, DN_FMT_ATTRIB char const *fmt, ...);
+DN_API bool                     DN_PathPop                                             (DN_Path *path);
+DN_API DN_Str8                  DN_Str8FromPath                                        (DN_Path const *path, DN_Str8 path_seperator, DN_Allocator allocator);
+DN_API DN_Str8                  DN_Str8FmtPathVArena                                   (DN_Str8 path_seperator, DN_Arena *arena, char const *fmt, va_list args);
+DN_API DN_Str8                  DN_Str8FmtPathArena                                    (DN_Str8 path_seperator, DN_Arena *arena, DN_FMT_ATTRIB char const *fmt, ...);
+DN_API DN_Str8                  DN_Str8FmtPathVPool                                    (DN_Str8 path_seperator, DN_Pool  *pool,  char const *fmt, va_list args);
+DN_API DN_Str8                  DN_Str8FmtPathPool                                     (DN_Str8 path_seperator, DN_Pool  *pool,  DN_FMT_ATTRIB char const *fmt, ...);
+DN_API DN_Str8                  DN_Str8FmtOsPathArena                                  (DN_Arena *arena, DN_FMT_ATTRIB char const *fmt, ...);
+DN_API DN_Str8                  DN_Str8FmtOsPathPool                                   (DN_Pool  *pool,  DN_FMT_ATTRIB char const *fmt, ...);
+
 DN_API int                      DN_UTF8Encode                                          (DN_U8 utf8[4], DN_U32 codepoint);
 DN_API int                      DN_UTF16Encode                                         (DN_U16 utf16[2], DN_U32 codepoint);
 DN_API DN_UTF8DecodeResult      DN_UTF8Decode                                          (DN_Str8 stream);
@@ -3319,7 +3322,14 @@ DN_API void                     DN_ProfilerFmtToStdout
 DN_API DN_F64                   DN_ProfilerSecFromTsc                                  (DN_Profiler *profiler, DN_U64 duration_tsc);
 DN_API DN_F64                   DN_ProfilerMsFromTsc                                   (DN_Profiler *profiler, DN_U64 duration_tsc);
 
-DN_API void                     DN_QSort                                               (void *array, DN_USize array_size, DN_USize elem_size, void *user_context, DN_QSortCompareFunc *compare);
+DN_API void                     DN_QSort_                                              (void *array, DN_USize array_size, DN_USize elem_size, void *user_context, DN_QSortCompareFunc *compare);
+#if defined(__cplusplus)
+template <typename T> void      DN_QSortT                                              (T *array, DN_USize array_size, void *user_context, DN_QSortCompareFunc *compare);
+#define                         DN_QSort(array, array_size, user_context, compare)     DN_QSortT(array, array_size, user_context, compare)
+#else
+#define                         DN_QSort(array, array_size, user_context, compare)     DN_QSort_(array, array_size, sizeof(*array), user_context, compare)
+#endif
+
 DN_API bool                     DN_QSortCompareStr8NaturalAsc                          (void const* lhs, void const *rhs, void *user_context);
 DN_API bool                     DN_QSortCompareStr8NaturalDesc                         (void const* lhs, void const *rhs, void *user_context);
 DN_API bool                     DN_QSortCompareStr8LexicographicAsc                    (void const* lhs, void const *rhs, void *user_context);
@@ -3348,12 +3358,12 @@ DN_API DN_F32                   DN_Pcg32NextF32
 DN_API DN_F64                   DN_Pcg32NextF64                                        (DN_Pcg32 *rng);
 DN_API void                     DN_Pcg32Advance                                        (DN_Pcg32 *rng, DN_U64 delta);
 
-#if !defined(DN_Fnv1a32_SEED)
+#if !defined(DN_FNV1A32_SEED)
-  #define DN_Fnv1a32_SEED 2166136261U
+  #define DN_FNV1A32_SEED 2166136261U
 #endif
 
-#if !defined(DN_Fnv1a64_SEED)
+#if !defined(DN_FNV1A64_SEED)
-  #define DN_Fnv1a64_SEED 14695981039346656037ULL
+  #define DN_FNV1A64_SEED 14695981039346656037ULL
 #endif
 
 DN_API DN_U32                   DN_Fnv1aHashU32FromBytes                               (void const *bytes, DN_USize count, DN_U32 seed);
@@ -3499,10 +3509,16 @@ DN_API DN_V2U16&               operator/=
 DN_API DN_V2U16&               operator-=                                              (DN_V2U16& lhs, DN_V2U16 rhs);
 DN_API DN_V2U16&               operator+=                                              (DN_V2U16& lhs, DN_V2U16 rhs);
 
-#define                        DN_V2U32Zero                                            DN_Literal(DN_V2U32){{(DN_U32)(0), (DN_U32)(0)}}
+// NOTE: DN_V2F32
-#define                        DN_V2U32One                                             DN_Literal(DN_V2U32){{(DN_U32)(1), (DN_U32)(1)}}
+// API
-#define                        DN_V2U32From1N(x)                                       DN_Literal(DN_V2U32){{(DN_U32)(x), (DN_U32)(x)}}
+//   DN_V2F32Rotate
-#define                        DN_V2U32From2N(x, y)                                    DN_Literal(DN_V2U32){{(DN_U32)(x), (DN_U32)(y)}}
+//     Rotate a vector using the precomputed cosine and sine value of the angle (e.g.
+//     `cos_a => cos(your_angle * 2.f * DN_PiF32)` and `sin_a => sinf(your_angle * 2.f * DN_PiF32)`)
+#define                        DN_V2U32Zero                                            DN_Literal(DN_V2U32){{(DN_U32)(0),    (DN_U32)(0)}}
+#define                        DN_V2U32One                                             DN_Literal(DN_V2U32){{(DN_U32)(1),    (DN_U32)(1)}}
+#define                        DN_V2U32From1N(x)                                       DN_Literal(DN_V2U32){{(DN_U32)(x),    (DN_U32)(x)}}
+#define                        DN_V2U32From2N(x, y)                                    DN_Literal(DN_V2U32){{(DN_U32)(x),    (DN_U32)(y)}}
+#define                        DN_V2U32FromV2(v2)                                      DN_Literal(DN_V2U32){{(DN_U32)(v2.x), (DN_U32)(v2.y)}}
 
 #define                        DN_V2F32Zero                                            DN_Literal(DN_V2F32){{(DN_F32)(0),    (DN_F32)(0)}}
 #define                        DN_V2F32One                                             DN_Literal(DN_V2F32){{(DN_F32)(1),    (DN_F32)(1)}}
@@ -3511,6 +3527,7 @@ DN_API DN_V2U16&               operator+=
 #define                        DN_V2F32FromV2(xy)                                      DN_Literal(DN_V2F32){{(DN_F32)(xy).x, (DN_F32)(xy).y}}
 
 DN_API DN_V2F32                DN_V2F32Lerp                                            (DN_V2F32 a, DN_F32 t, DN_V2F32 b);
+DN_API DN_V2F32                DN_V2F32Rotate                                          (DN_V2F32 v, DN_F32 cos_a, DN_F32 sin_a);
 
 DN_API bool                    operator!=                                              (DN_V2F32  lhs, DN_V2F32  rhs);
 DN_API bool                    operator==                                              (DN_V2F32  lhs, DN_V2F32  rhs);
@@ -3580,7 +3597,7 @@ DN_API DN_F32                  DN_V2F32Area
 
 // NOTE: Grayscale co-efficients from:
 //   https://github.com/EpicGames/UnrealEngine/blob/260bb2e1c5610b31c63a36206eedd289409c5f11/Engine/Source/Runtime/Core/Private/Math/Color.cpp#L304
-DN_V3F32 static const          DN_V3F32_Rgb_LUMINANCE = DN_V3F32From3N(0.3f, 0.59f, 0.11f);
+DN_V3F32 static const          DN_V3F32_RGB_LUMINANCE = DN_V3F32From3N(0.3f, 0.59f, 0.11f);
 
 DN_API bool                    operator==                                              (DN_V3F32  lhs, DN_V3F32  rhs);
 DN_API bool                    operator!=                                              (DN_V3F32  lhs, DN_V3F32  rhs);
@@ -4596,8 +4613,8 @@ DN_API void *                    DN_OS_MemAlloc                               (D
 DN_API void                      DN_OS_MemDealloc                             (void *ptr);
 
 DN_API DN_Date                   DN_OS_DateLocalTimeNow                       ();
-DN_API DN_Str8x32                DN_OS_DateLocalTimeStr8Now                   (char date_separator = '-', char hms_separator = ':');
+DN_API DN_Str8x32                DN_OS_DateLocalTimeStr8Now                   (char date_seperator = '-', char hms_seperator = ':');
-DN_API DN_Str8x32                DN_OS_DateLocalTimeStr8                      (DN_Date time, char date_separator = '-', char hms_separator = ':');
+DN_API DN_Str8x32                DN_OS_DateLocalTimeStr8                      (DN_Date time, char date_seperator = '-', char hms_seperator = ':');
 DN_API DN_U64                    DN_OS_DateUnixTimeNs                         ();
 #define                          DN_OS_DateUnixTimeUs()                       (DN_OS_DateUnixTimeNs() / 1000)
 #define                          DN_OS_DateUnixTimeMs()                       (DN_OS_DateUnixTimeNs() / (1000 * 1000))
@@ -4696,24 +4713,6 @@ DN_API bool                      DN_OS_PathIsDir                              (D
 DN_API bool                      DN_OS_PathMakeDir                            (DN_Str8 path);
 DN_API bool                      DN_OS_PathIterateDir                         (DN_Str8 path, DN_OSDirIterator *it);
 
-DN_API bool                      DN_OS_PathAddRef                             (DN_Arena *arena, DN_OSPath *fs_path, DN_Str8 path);
-DN_API bool                      DN_OS_PathAdd                                (DN_Arena *arena, DN_OSPath *fs_path, DN_Str8 path);
-DN_API bool                      DN_OS_PathAddF                               (DN_Arena *arena, DN_OSPath *fs_path, DN_FMT_ATTRIB char const *fmt, ...);
-DN_API bool                      DN_OS_PathPop                                (DN_OSPath *fs_path);
-DN_API DN_Str8                   DN_OS_PathBuildWithSeparatorAllocator        (DN_Allocator allocator, DN_OSPath const *fs_path, DN_Str8 path_separator);
-DN_API DN_Str8                   DN_OS_PathToArena                            (DN_Arena *arena, DN_Str8 path, DN_Str8 path_separtor);
-DN_API DN_Str8                   DN_OS_PathToPool                             (DN_Pool  *pool,  DN_Str8 path, DN_Str8 path_separtor);
-DN_API DN_Str8                   DN_OS_PathToFmtArena                         (DN_Arena *arena, DN_Str8 path_separator, DN_FMT_ATTRIB char const *fmt, ...);
-DN_API DN_Str8                   DN_OS_PathToFmtPool                          (DN_Pool  *pool,  DN_Str8 path_separator, DN_FMT_ATTRIB char const *fmt, ...);
-DN_API DN_Str8                   DN_OS_PathArena                              (DN_Arena *arena, DN_Str8 path);
-DN_API DN_Str8                   DN_OS_PathPool                               (DN_Pool  *pool,  DN_Str8 path);
-DN_API DN_Str8                   DN_OS_PathFmtArena                           (DN_Arena *arena, DN_FMT_ATTRIB char const *fmt, ...);
-DN_API DN_Str8                   DN_OS_PathFmtPool                            (DN_Pool  *pool,  DN_FMT_ATTRIB char const *fmt, ...);
-
-#define                          DN_OS_PathBuildFwdSlash(allocator, fs_path)  DN_OS_PathBuildWithSeparatorAllocator(allocator, fs_path, DN_Str8Lit("/"))
-#define                          DN_OS_PathBuildBackSlash(allocator, fs_path) DN_OS_PathBuildWithSeparatorAllocator(allocator, fs_path, DN_Str8Lit("\\"))
-#define                          DN_OS_PathBuild(allocator, fs_path)          DN_OS_PathBuildWithSeparatorAllocator(allocator, fs_path, DN_OSPathSeparatorStr8)
-
 DN_API void                      DN_OS_Exit                                   (int32_t exit_code);
 DN_API DN_OSExecArgs             DN_OS_ExecArgsDefault                        ();
 DN_API DN_OSExecResult           DN_OS_ExecPump                               (DN_OSExecAsyncHandle handle, char *stdout_buffer, size_t *stdout_size, char *stderr_buffer, size_t *stderr_size, DN_U32 timeout_ms, DN_ErrSink  *err);

Source/dn_seshc.cpp

@@ -0,0 +1,301 @@
+#include "dn_seshc.h"
+
+struct DN_SHMsgSendAsyncContext_
+{
+  bool             send_success;
+  DN_Arena*        arena;
+  DN_SHCLIArgs     args;
+  DN_SHMsgSendData send;
+  DN_Str8          msg;
+  bool             detached;
+};
+
+DN_SHCLIArgs DN_SH_CLIArgsCopy(DN_SHCLIArgs const *src, DN_Arena *arena)
+{
+  DN_SHCLIArgs result   = {};
+  result                = *src;
+  result.exe_path       = DN_Str8FromStr8Arena(src->exe_path, arena);
+  result.ini_path       = DN_Str8FromStr8Arena(src->ini_path, arena);
+  result.seed_node_url  = DN_Str8FromStr8Arena(src->seed_node_url, arena);
+  return result;
+}
+
+DN_Str8 DN_SH_CLIOptionsStr8()
+{
+  DN_Str8 result = DN_Str8Lit(
+"SESHC OPTIONS (note all options must be set to activate Seshc):\n"
+"  --seshc-exe-path <path>              Path to the Seshc EXE file to invoke for sending messages\n"
+"  --seshc-ini-path <path>              Path to the .ini file to load Seshc arguments from\n"
+"                                       (such as account secrets, display name, recipient...)\n"
+"  --seshc-seed-node <url>              URL to the Session seed node for determining the nodes to\n"
+"                                       send the message to\n"
+  );
+  return result;
+}
+
+DN_SHCLIEatArgResult DN_SH_CLIEatArg(DN_SHCLIArgs *args, char const **arg_ptr, int arg_count)
+{
+  DN_SHCLIEatArgResult result = {};
+  result.arg_ptr           = arg_ptr;
+  result.arg_count         = arg_count;
+
+  DN_Str8 arg = {};
+  if (arg_count)
+    arg = DN_Str8FromCStr8(*result.arg_ptr);
+
+  // NOTE: Try handling the argument if we recognise it
+  {
+    if (!result.eaten && DN_Str8EqInsensitive(arg, DN_Str8Lit("--seshc-exe-path"))) {
+      (void)DN_ArgShift(result.arg_ptr, result.arg_count);
+      result.eaten   = true;
+      args->exe_path = DN_Str8FromCStr8(DN_ArgShift(result.arg_ptr, result.arg_count));
+
+      if (DN_OS_PathInfo(args->exe_path).type != DN_OSPathInfoType_File) {
+        result.error_msg = DN_Str8Lit("Seshc executable path does not point to a file");
+        result.error_arg = args->exe_path;
+        args->exe_path   = {};
+      }
+    }
+
+    if (!result.eaten && DN_Str8EqInsensitive(arg, DN_Str8Lit("--seshc-ini-path"))) {
+      (void)DN_ArgShift(result.arg_ptr, result.arg_count);
+      result.eaten   = true;
+      args->ini_path = DN_Str8FromCStr8(DN_ArgShift(result.arg_ptr, result.arg_count));
+
+      if (DN_OS_PathInfo(args->ini_path).type != DN_OSPathInfoType_File) {
+        result.error_msg = DN_Str8Lit("Seshc ini path does not point to a file");
+        result.error_arg = args->ini_path;
+        args->ini_path   = {};
+      }
+    }
+
+    if (!result.eaten && DN_Str8EqInsensitive(arg, DN_Str8Lit("--seshc-seed-node"))) {
+      (void)DN_ArgShift(result.arg_ptr, result.arg_count);
+      result.eaten        = true;
+      args->seed_node_url = DN_Str8FromCStr8(DN_ArgShift(result.arg_ptr, result.arg_count));
+    }
+  }
+
+  if (args->seed_node_url.count && args->exe_path.count && args->ini_path.count)
+    args->valid = true;
+  return result;
+}
+
+bool DN_SH_MsgSendBlockingFmt(DN_SHMsgSendData send, DN_SHCLIArgs *cli_args, char const *fmt, ...)
+{
+  bool result = false;
+  if (cli_args->valid) {
+    DN_TcScratch scratch = DN_TcScratchBeginArena(nullptr, 0);
+
+    va_list args;
+    va_start(args, fmt);
+    DN_Str8 msg = DN_Str8FmtVArena(&scratch.arena, fmt, args);
+    va_end(args);
+
+    DN_Str8 account_secret_arg = DN_Str8Lit("--account-secret");
+    DN_Str8 seed_node_url_arg  = DN_Str8Lit("--seed-node-url");
+    DN_Str8 display_name_arg   = DN_Str8Lit("--display-name");
+    DN_Str8 ini_path_arg       = DN_Str8Lit("--ini-path");
+    DN_Str8 send_arg           = DN_Str8Lit("send");
+
+    DN_Str8  cmds[16]   = {};
+    DN_USize cmds_count = 0;
+    DN_LArrayAppend(cmds, &cmds_count, cli_args->exe_path);
+
+    DN_LArrayAppend(cmds, &cmds_count, account_secret_arg);
+    DN_LArrayAppend(cmds, &cmds_count, send.account_secret);
+
+    DN_LArrayAppend(cmds, &cmds_count, seed_node_url_arg);
+    DN_LArrayAppend(cmds, &cmds_count, cli_args->seed_node_url);
+
+    if (send.display_name.count) {
+      DN_LArrayAppend(cmds, &cmds_count, display_name_arg);
+      DN_LArrayAppend(cmds, &cmds_count, send.display_name);
+    }
+
+    DN_LArrayAppend(cmds, &cmds_count, ini_path_arg);
+    DN_LArrayAppend(cmds, &cmds_count, cli_args->ini_path);
+
+    DN_LArrayAppend(cmds, &cmds_count, send_arg);
+    DN_LArrayAppend(cmds, &cmds_count, send.recipient);
+
+    DN_LArrayAppend(cmds, &cmds_count, msg);
+
+    DN_Str8Slice cmd_line = {};
+    cmd_line.data         = cmds;
+    cmd_line.count        = cmds_count;
+    DN_OSExecResult exec  = DN_OS_Exec(cmd_line, DN_OS_ExecArgsDefault(), &scratch.arena, nullptr);
+    result                = exec.os_error_code == 0 && exec.exit_code == 0;
+    if (!result) {
+      DN_LogErrorF("Error sending message to %.*s (exit code: %d, os: %d): %.*s",
+                   DN_Str8PrintFmt(send.recipient),
+                   exec.exit_code,
+                   exec.os_error_code,
+                   DN_Str8PrintFmt(exec.stderr_text));
+    }
+    DN_TcScratchEnd(&scratch);
+
+  }
+  return result;
+}
+
+static int DN_SH_MsgSendDetachedFmtThreadFunc_(DN_OSThread *thread)
+{
+  DN_SHMsgSendAsyncContext_ *context = DN_Cast(DN_SHMsgSendAsyncContext_ *) thread->user_context;
+  context->send_success              = DN_SH_MsgSendBlockingFmt(context->send, &context->args, "%.*s", DN_Str8PrintFmt(context->msg));
+  if (context->detached)
+    DN_ArenaDeinit(context->arena);
+  return 0;
+}
+
+static DN_SHMsgSendAsyncHandle DN_SH_MsgSendAsyncFmtVMaybeDetached_(DN_SHMsgSendData send, DN_SHCLIArgs *cli_args, DN_Arena *arena, bool detached, char const *fmt, va_list args)
+{
+  DN_SHMsgSendAsyncHandle result = {};
+  if (!cli_args->valid)
+    return result;
+
+  // NOTE: Setup context
+  DN_SHMsgSendAsyncContext_ *context = DN_ArenaNewZ(arena, DN_SHMsgSendAsyncContext_);
+  context->args                      = DN_SH_CLIArgsCopy(cli_args, arena);
+  context->send                      = send;
+  context->arena                     = arena;
+  context->msg                       = DN_Str8FmtVArena(arena, fmt, args);
+  context->detached                  = detached;
+
+  // NOTE: Execute and forget
+  DN_OSThreadInitArgs thread_args = DN_OS_ThreadInitArgsDefault();
+  if (detached)
+    thread_args.flags |= DN_OSThreadFlags_Detached;
+
+  DN_OS_ThreadInit(&result.thread, DN_SH_MsgSendDetachedFmtThreadFunc_, thread_args, context);
+  return result;
+}
+
+void DN_SH_MsgSendDetachedFmt(DN_SHMsgSendData send, DN_SHCLIArgs *cli_args, char const *fmt, ...)
+{
+  DN_Arena  arena_stack = DN_OS_ArenaFromHeapVirtual(0, 0, DN_MemFlags_Nil);
+  DN_Arena *arena       = DN_ArenaNewZ(&arena_stack, DN_Arena);
+  *arena                = arena_stack;
+
+  va_list args;
+  va_start(args, fmt);
+  DN_SH_MsgSendAsyncFmtVMaybeDetached_(send, cli_args, arena, /*detached=*/ true, fmt, args);
+  va_end(args);
+}
+
+DN_SHMsgSendAsyncHandle DN_SH_MsgSendAsyncFmt(DN_SHMsgSendData send, DN_SHCLIArgs *cli_args, DN_Arena *arena, char const *fmt, ...)
+{
+  va_list args;
+  va_start(args, fmt);
+  DN_SHMsgSendAsyncHandle result = DN_SH_MsgSendAsyncFmtVMaybeDetached_(send, cli_args, arena, /*detached=*/ false, fmt, args);
+  va_end(args);
+  return result;
+}
+
+DN_SHMsgSendAsyncStatus DN_SH_MsgSendAsyncWait(DN_SHMsgSendAsyncHandle *handle, DN_U32 timeout_ms)
+{
+  DN_SHMsgSendAsyncStatus result = DN_SHMsgSendAsyncStatus_Success;
+  if (handle && handle->thread.user_context) {
+    bool joined = DN_OS_ThreadJoin(&handle->thread, timeout_ms, DN_TcDeinitArenas_Yes);
+    if (joined) {
+      DN_SHMsgSendAsyncContext_ *context = DN_Cast(DN_SHMsgSendAsyncContext_ *) handle->thread.user_context;
+      result                             = context->send_success ? DN_SHMsgSendAsyncStatus_Success : DN_SHMsgSendAsyncStatus_Failed;
+      *handle                            = {};
+    } else {
+      result = DN_SHMsgSendAsyncStatus_Timeout;
+    }
+  }
+  return result;
+}
+
+void DN_SH_LogBroadcastFmtV(DN_SHLogMode mode, DN_LogType type, DN_SHMsgSendData send, DN_SHCLIArgs *cli_args, DN_Str8 short_desc, char const *fmt, va_list args)
+{
+  DN_TcScratch scratch = DN_TcScratchBeginArena(nullptr, 0);
+  DN_Str8      msg     = DN_Str8FmtVArena(&scratch.arena, fmt, args);
+  DN_Str8      prefix  = {};
+  switch (type) {
+    case DN_LogType_Debug:   prefix = DN_Str8Lit("🐞 "); break;
+    case DN_LogType_Info:    prefix = DN_Str8Lit("ℹ️ "); break;
+    case DN_LogType_Warning: prefix = DN_Str8Lit("⚠️ "); break;
+    case DN_LogType_Error:   prefix = DN_Str8Lit("🚨 "); break;
+    case DN_LogType_Count:   break;
+  }
+  DN_LogF(type, "%.*s%.*s. %.*s", DN_Str8PrintFmt(prefix), DN_Str8PrintFmt(short_desc), DN_Str8PrintFmt(msg));
+
+  DN_Date date = DN_OS_DateLocalTimeNow();
+
+  // NOTE: 12-hour conversion
+  DN_U8 hour12 = date.hour % 12;
+  if (hour12 == 0)
+    hour12 = 12;
+  char const *am_pm = date.hour < 12 ? "AM" : "PM";
+
+  // Time-of-day emoji
+  DN_Str8 time_emoji = {};
+  if (date.hour >= 5 && date.hour <= 11)
+    time_emoji = DN_Str8Lit("☀️");
+  else if (date.hour >= 12 && date.hour <= 16)
+    time_emoji = DN_Str8Lit("🌤️");
+  else if (date.hour >= 17 && date.hour <= 19)
+    time_emoji = DN_Str8Lit("🌅");
+  else if (date.hour >= 20 && date.hour <= 23)
+    time_emoji = DN_Str8Lit("✨");
+  else
+    time_emoji = DN_Str8Lit("🌑");
+
+  if (mode == DN_SHLogMode_Detached) {
+    DN_SH_MsgSendDetachedFmt(send,
+                             cli_args,
+                             "%.*s%.*s\n"
+                             "%.*s %u-%02u-%02u %u:%02u:%02u %s%s"
+                             "%.*s",
+                             DN_Str8PrintFmt(prefix),
+                             DN_Str8PrintFmt(short_desc),
+                             DN_Str8PrintFmt(time_emoji),
+                             date.year,
+                             date.month,
+                             date.day,
+                             hour12,
+                             date.minutes,
+                             date.seconds,
+                             am_pm,
+                             msg.count ? "\n" : "",
+                             DN_Str8PrintFmt(msg));
+  } else {
+    DN_Assert(mode == DN_SHLogMode_Blocking);
+    DN_SH_MsgSendBlockingFmt(send,
+                             cli_args,
+                             "%.*s %.*s\n"
+                             "%.*s %u-%02u-%02u %u:%02u:%02u %s%s"
+                             "%.*s",
+                             DN_Str8PrintFmt(prefix),
+                             DN_Str8PrintFmt(short_desc),
+                             DN_Str8PrintFmt(time_emoji),
+                             date.year,
+                             date.month,
+                             date.day,
+                             hour12,
+                             date.minutes,
+                             date.seconds,
+                             am_pm,
+                             msg.count ? "\n" : "",
+                             DN_Str8PrintFmt(msg));
+  }
+  DN_TcScratchEnd(&scratch);
+}
+
+void DN_SH_LogBroadcastBlockingFmt(DN_LogType type, DN_SHMsgSendData send, DN_SHCLIArgs *cli_args, DN_Str8 short_desc, char const *fmt, ...)
+{
+  va_list args;
+  va_start(args, fmt);
+  DN_SH_LogBroadcastFmtV(DN_SHLogMode_Blocking, type, send, cli_args, short_desc, fmt, args);
+  va_end(args);
+}
+
+void DN_SH_LogBroadcastDetachedFmt(DN_LogType type, DN_SHMsgSendData send, DN_SHCLIArgs *cli_args, DN_Str8 short_desc, char const *fmt, ...)
+{
+  va_list args;
+  va_start(args, fmt);
+  DN_SH_LogBroadcastFmtV(DN_SHLogMode_Detached, type, send, cli_args, short_desc, fmt, args);
+  va_end(args);
+}

Source/dn_seshc.h

@@ -0,0 +1,82 @@
+#if !defined(DN_SESHC_H)
+#define DN_SESHC_H
+
+#if defined(_CLANGD)
+  #define DN_WITH_OS 1
+  #include "../dn.h"
+#endif
+
+struct DN_SHCLIArgs
+{
+  bool    valid;
+  DN_Str8 exe_path;
+  DN_Str8 ini_path;
+  DN_Str8 seed_node_url;
+};
+
+struct DN_SHCLIEatArgResult
+{
+  bool         eaten;
+  DN_Str8      error_msg; // Parsing error message. String is immutably stored in the data-segment w/ program lifetime.
+  DN_Str8      error_arg; // Argument that caused the parsing error
+  char const **arg_ptr;   // Next argument pointer that that the caller should proceed from
+  DN_USize     arg_count; // Next argument count that that the caller should assume
+};
+
+struct DN_SHMsgSendData
+{
+  DN_Str8 recipient;      // Either `ini:<section.key>` or "05-prefix session account ID"
+  DN_Str8 account_secret; // Seshc EXE --account-secret format
+  DN_Str8 display_name;
+};
+
+struct DN_SHMsgSendAsyncHandle
+{
+  DN_OSThread thread;
+};
+
+enum DN_SHLogMode
+{
+  DN_SHLogMode_Blocking,
+  DN_SHLogMode_Detached,
+};
+
+enum DN_SHMsgSendAsyncStatus
+{
+  DN_SHMsgSendAsyncStatus_Timeout,
+  DN_SHMsgSendAsyncStatus_Success,
+  DN_SHMsgSendAsyncStatus_Failed,
+};
+
+
+// NOTE: Seshc
+// Overview
+//   Helper library that provides some useful APIs for programatically calling the Seshc CLI
+//   executable to send messages from your C/C++ application.
+
+// API
+//   DN_SH_MsgSendDetachedFmt
+//     Send a 1-on-1 message with a background thread that is spawned on demand and detached. If the
+//     application exits before this thread has completed sending the message, the message will not
+//     be sent.
+
+//   DN_SH_MsgSendBlockingFmt
+//     Send a 1-on-1 message using the current executing thread, blocking control-flow until the
+//     message has been sent. Returns true if the send was successful, false otherwise.
+
+//   DN_SH_MsgSendAsyncFmt
+//     Send a 1-on-1 message with a background thread that is spawned on demand. A handle to the
+//     thread is returned that can be waited on.
+
+DN_SHCLIArgs            DN_SH_CLIArgsCopy             (DN_SHCLIArgs const *src, DN_Arena *arena);
+DN_Str8                 DN_SH_CLIOptionsStr8          ();
+DN_SHCLIEatArgResult    DN_SH_CLIEatArg               (DN_SHCLIArgs *args, char const **arg_ptr, int arg_count);
+bool                    DN_SH_MsgSendBlockingFmt      (DN_SHMsgSendData send, DN_SHCLIArgs *cli_args, char const *fmt, ...);
+void                    DN_SH_MsgSendDetachedFmt      (DN_SHMsgSendData send, DN_SHCLIArgs *cli_args, char const *fmt, ...);
+DN_SHMsgSendAsyncHandle DN_SH_MsgSendAsyncFmt         (DN_SHMsgSendData send, DN_SHCLIArgs *cli_args, DN_Arena *arena, char const *fmt, ...);
+DN_SHMsgSendAsyncStatus DN_SH_MsgSendAsyncWait        (DN_SHMsgSendAsyncHandle *handle, DN_U32 timeout_ms);
+void                    DN_SH_LogBroadcastFmtV        (DN_SHLogMode mode, DN_LogType type, DN_SHMsgSendData send, DN_SHCLIArgs *cli_args, DN_Str8 short_desc, char const *fmt, va_list args);
+void                    DN_SH_LogBroadcastBlockingFmt (DN_LogType type, DN_SHMsgSendData send, DN_SHCLIArgs *cli_args, DN_Str8 short_desc, char const *fmt, ...);
+void                    DN_SH_LogBroadcastDetachedFmt (DN_LogType type, DN_SHMsgSendData send, DN_SHCLIArgs *cli_args, DN_Str8 short_desc, char const *fmt, ...);
+
+#endif // #if !defined(DN_SESHC_H)

Source/dn_tests.cpp

@@ -1,5 +1,11 @@
 #if DN_WITH_NET_CURL
   #define DN_NO_WINDOWS_H_REPLACEMENT_HEADER
+  #define CURL_STATICLIB
+  #include <curl/curl.h>
+#endif
+
+#if defined(__EMSCRIPTEN__)
+  #define DN_WITH_NET_EMSCRIPTEN 1
 #endif
 
 #define DN_PARANOIA_LEVEL 1
@@ -7,15 +13,6 @@
 #define DN_WITH_NET       1
 #define DN_WITH_TESTS     1
 #include "dn.h"
-
-#if DN_WITH_NET_CURL
-  #define CURL_STATICLIB
-  #include <curl/curl.h>
-#endif
-
-#if defined(DN_PLATFORM_EMSCRIPTEN)
-  #define DN_WITH_NET_EMSCRIPTEN 1
-#endif
 #include "dn.cpp"
 
 #define DN_SHA3_WITH_TESTS

single_header_generator.cpp

@@ -65,7 +65,7 @@ static void AppendCppFileLineByLine(DN_Str8Builder *dest, DN_Str8 cpp_path)
           line                     = DN_Str8FmtArena(&scratch.arena, "%S// DN: Single header generator commented out => %S", find.start_to_before_match, DN_Str8TrimWhitespaceAround(find.match_to_end_of_buffer));
           DN_Str8 rel_include_path = DN_Str8TrimWhitespaceAround(find.after_match_to_end_of_buffer);
           DN_Str8 root_dir         = DN_Str8FileDirectoryFromPath(cpp_path);
-          extra_include_path       = DN_OS_PathFmtArena(&scratch.arena, "%S/%S", root_dir, DN_Str8TrimSuffixSensitive(rel_include_path, DN_Str8Lit("\"")));
+          extra_include_path       = DN_Str8FmtOsPathArena(&scratch.arena, "%S/%S", root_dir, DN_Str8TrimSuffixSensitive(rel_include_path, DN_Str8Lit("\"")));
         }
       }
     }
@@ -113,7 +113,7 @@ int main(int argc, char **argv)
     DN_Str8Builder builder = DN_Str8BuilderFromArena(&scratch.arena);
     DN_Str8        suffix  = type == FileType_Header ? DN_Str8Lit("h") : DN_Str8Lit("cpp");
     for (DN_ForItCArray(it, DN_Str8 const, REL_FILE_PATHS)) {
-      DN_Str8 path = DN_OS_PathFmtArena(&scratch.arena, "%S/%S.%S", dn_root_dir, *it.data, suffix);
+      DN_Str8 path = DN_Str8FmtOsPathArena(&scratch.arena, "%S/%S.%S", dn_root_dir, *it.data, suffix);
       AppendCppFileLineByLine(&builder, path);
     }
 
@@ -121,7 +121,7 @@ int main(int argc, char **argv)
     DN_Str8BuilderPrependF(&builder, "// Generated by the DN single header generator %04u-%02u-%02u %02u:%02u:%02u\n\n", date.year, date.month, date.day, date.hour, date.minutes, date.seconds);
 
     DN_Str8     buffer             = DN_Str8TrimWhitespaceAround(DN_Str8FromStr8BuilderArena(&builder, &scratch.arena));
-    DN_Str8     single_header_path = DN_OS_PathFmtArena(&scratch.arena, "%S/dn_single_header.%S", output_dir, suffix);
+    DN_Str8     single_header_path = DN_Str8FmtOsPathArena(&scratch.arena, "%S/dn_single_header.%S", output_dir, suffix);
     DN_ErrSink *err                = DN_TcErrSinkBeginDefault();
     DN_OS_FileWriteAllSafe(single_header_path, buffer, err);
     DN_ErrSinkEndExitIfErrorF(err, -1, "Failed to write Single header file '%S'", single_header_path);