Replace all snprintf() calls with M_snprintf().

The Windows API has an _snprintf function that is not the same as
Unix's snprintf(): if the string is truncated then no trailing NUL
character is appended. This makes the function unsafe. Define a
replacement/wrapper called M_snprintf that works the same but always
appends a trailing NUL, for safety on Windows and other OSes that
behave like this.

Do the same thing for vsnprintf(), and update HACKING to list
snprintf/vsnprintf as forbidden functions. This fixes #375;
thanks to Quasar for pointing out the different behavior of these
functions.

1 files changed, 2 insertions, 2 deletions

diff --git a/src/i_video.c b/src/i_video.c
index 823209b8..7c739c17 100644
--- a/src/i_video.c
+++ b/src/i_video.c
@@ -1820,7 +1820,7 @@ static void SetWindowPositionVars(void)
     }
     else if (sscanf(window_position, "%i,%i", &x, &y) == 2)
     {
-        snprintf(buf, sizeof(buf), "SDL_VIDEO_WINDOW_POS=%i,%i", x, y);
+        M_snprintf(buf, sizeof(buf), "SDL_VIDEO_WINDOW_POS=%i,%i", x, y);
         putenv(buf);
     }
 }
@@ -1990,7 +1990,7 @@ void I_InitGraphics(void)
         int winid;
 
         sscanf(env, "0x%x", &winid);
-        snprintf(winenv, sizeof(winenv), "SDL_WINDOWID=%i", winid);
+        M_snprintf(winenv, sizeof(winenv), "SDL_WINDOWID=%i", winid);
 
         putenv(winenv);
     }