X-Git-Url: https://git.tokkee.org/?a=blobdiff_plain;f=compat%2Fsnprintf.c;h=e1e0e7543d9414726122c121b7909bf73809a81a;hb=48058f5df49fb9005418a7d025b374988908c0b5;hp=580966e56a3455b9970b7eef33143c1e9c57d41c;hpb=4d9e42f8f11c57b32b976a943c8ddaf6214e64b8;p=git.git

diff --git a/compat/snprintf.c b/compat/snprintf.c
index 580966e56..e1e0e7543 100644
--- a/compat/snprintf.c
+++ b/compat/snprintf.c
@@ -2,12 +2,19 @@
 
 /*
  * The size parameter specifies the available space, i.e. includes
- * the trailing NUL byte; but Windows's vsnprintf expects the
- * number of characters to write without the trailing NUL.
+ * the trailing NUL byte; but Windows's vsnprintf uses the entire
+ * buffer and avoids the trailing NUL, should the buffer be exactly
+ * big enough for the result. Defining SNPRINTF_SIZE_CORR to 1 will
+ * therefore remove 1 byte from the reported buffer size, so we
+ * always have room for a trailing NUL byte.
  */
 #ifndef SNPRINTF_SIZE_CORR
+#if defined(WIN32) && (!defined(__GNUC__) || __GNUC__ < 4)
+#define SNPRINTF_SIZE_CORR 1
+#else
 #define SNPRINTF_SIZE_CORR 0
 #endif
+#endif
 
 #undef vsnprintf
 int git_vsnprintf(char *str, size_t maxsize, const char *format, va_list ap)
@@ -17,6 +24,8 @@ int git_vsnprintf(char *str, size_t maxsize, const char *format, va_list ap)
 
 	if (maxsize > 0) {
 		ret = vsnprintf(str, maxsize-SNPRINTF_SIZE_CORR, format, ap);
+		if (ret == maxsize-1)
+			ret = -1;
 		/* Windows does not NUL-terminate if result fills buffer */
 		str[maxsize-1] = 0;
 	}
@@ -34,6 +43,8 @@ int git_vsnprintf(char *str, size_t maxsize, const char *format, va_list ap)
 			break;
 		s = str;
 		ret = vsnprintf(str, maxsize-SNPRINTF_SIZE_CORR, format, ap);
+		if (ret == maxsize-1)
+			ret = -1;
 	}
 	free(s);
 	return ret;