utility: Add initializer functions

source/utility.hpp

@@ -15,8 +15,6 @@
 // along with this program; if not, write to the Free Software
 // Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA
 
-#ifndef OBS_FFMPEG_UTILITY_HPP
-#define OBS_FFMPEG_UTILITY_HPP
 #pragma once
 
 #include "version.hpp"
@@ -45,4 +43,31 @@
 #define vstr(s) dstr(s)
 #define dstr(s) #s
 
-#endif OBS_FFMPEG_UTILITY_HPP
+// Initializer
+#ifdef __cplusplus
+#define INITIALIZER(f) \
+	static void f(void); \
+	struct f##_t_ { \
+		f##_t_(void) \
+		{ \
+			f(); \
+		} \
+	}; \
+	static f##_t_ f##_; \
+	static void   f(void)
+#elif defined(_MSC_VER)
+#pragma section(".CRT$XCU", read)
+#define INITIALIZER2_(f, p) \
+	static void f(void); \
+	__declspec(allocate(".CRT$XCU")) void (*f##_)(void) = f; \
+	__pragma(comment(linker, "/include:" p #f "_")) static void f(void)
+#ifdef _WIN64
+#define INITIALIZER(f) INITIALIZER2_(f, "")
+#else
+#define INITIALIZER(f) INITIALIZER2_(f, "_")
+#endif
+#else
+#define INITIALIZER(f) \
+	static void f(void) __attribute__((constructor)); \
+	static void f(void)
+#endif