Adding OS function.

harbour/source/rtl/environ.c

@@ -4,6 +4,94 @@
 
 #include <extend.h>
 
+HARBOUR OS()
+{
+/* TODO: add MSVC support but MSVC cannot detect any OS except Windows! */
+#if defined(__TURBOC__) || defined(__BORLANDC__)
+
+  /* detect OS/2 */
+  _AX = 0x2B01;
+  _CX = 0x4445;
+  _DX = 0x5351;
+  _AH = 0x30;
+  geninterrupt(0x21);
+  if(_AL >= 10)
+  {
+     _retc("OS/2");
+  }
+
+  /* detect Windows */
+  /* TODO: get Windows version (major, minor) */
+  _AX = 0x160A;
+  geninterrupt(0x2F);
+  if(_AX == 0)
+  {
+     _retc("Windows");
+  }
+
+#else
+
+  union REGS regs;
+
+  /* detect OS/2 */
+  regs.h.ah = 0x30;
+
+#if defined(__WATCOMC__) && defined(__386__)
+
+  int386(0x21, &regs, &regs);
+
+#else
+
+#if defined(__EMX__)
+
+  _int86(0x21, &regs, &regs);
+
+#else
+
+  int86(0x21, &regs, &regs);
+
+#endif /* __EMX__ */
+
+  if(regs.h.al >= 10)
+  {
+     _retc("OS/2");
+  }
+
+  /* TODO: get Windows version (major, minor) */
+  /* detect Windows */
+  regs.w.ax = 0x160A;
+
+#if defined(__WATCOMC__) && defined(__386__)
+
+  int386(0x2F, &regs, &regs);
+
+#else
+
+#if defined(__EMX__)
+
+  _int86(0x2F, &regs, &regs);
+
+#else
+
+  int86(0x2F, &regs, &regs);
+
+#endif /* EMX */
+
+  if(regs.x.ax == 0)
+  {
+     _retc("Windows");
+  }
+
+#endif /* WATCOMC */
+
+#endif /* __TURBOC__ or __BORLANDC__ */
+
+  /* fall through to MS-DOS */
+  /* TODO: detect other OSes */
+  /* TODO: detect MS-DOS version */
+  _retc("MS-DOS");
+}
+
 HARBOUR VERSION()
 {
    _retc( "Harbour alpha version" );