The original Quake 2 sources as originally released under the GPL license on December 21, 2001.

null/sys_null.c

@@ -0,0 +1,127 @@
+// sys_null.h -- null system driver to aid porting efforts
+
+#include "../qcommon/qcommon.h"
+#include "errno.h"
+
+int	curtime;
+
+unsigned	sys_frame_time;
+
+
+void Sys_mkdir (char *path)
+{
+}
+
+void Sys_Error (char *error, ...)
+{
+	va_list		argptr;
+
+	printf ("Sys_Error: ");	
+	va_start (argptr,error);
+	vprintf (error,argptr);
+	va_end (argptr);
+	printf ("\n");
+
+	exit (1);
+}
+
+void Sys_Quit (void)
+{
+	exit (0);
+}
+
+void	Sys_UnloadGame (void)
+{
+}
+
+void	*Sys_GetGameAPI (void *parms)
+{
+	return NULL;
+}
+
+char *Sys_ConsoleInput (void)
+{
+	return NULL;
+}
+
+void	Sys_ConsoleOutput (char *string)
+{
+}
+
+void Sys_SendKeyEvents (void)
+{
+}
+
+void Sys_AppActivate (void)
+{
+}
+
+void Sys_CopyProtect (void)
+{
+}
+
+char *Sys_GetClipboardData( void )
+{
+	return NULL;
+}
+
+void	*Hunk_Begin (int maxsize)
+{
+	return NULL;
+}
+
+void	*Hunk_Alloc (int size)
+{
+	return NULL;
+}
+
+void	Hunk_Free (void *buf)
+{
+}
+
+int		Hunk_End (void)
+{
+	return 0;
+}
+
+int		Sys_Milliseconds (void)
+{
+	return 0;
+}
+
+void	Sys_Mkdir (char *path)
+{
+}
+
+char	*Sys_FindFirst (char *path, unsigned musthave, unsigned canthave)
+{
+	return NULL;
+}
+
+char	*Sys_FindNext (unsigned musthave, unsigned canthave)
+{
+	return NULL;
+}
+
+void	Sys_FindClose (void)
+{
+}
+
+void	Sys_Init (void)
+{
+}
+
+
+//=============================================================================
+
+void main (int argc, char **argv)
+{
+	Qcommon_Init (argc, argv);
+
+	while (1)
+	{
+		Qcommon_Frame (0.1);
+	}
+}
+
+