Handle the case when MINGW32 vsnprintf returns -1

MINGW32 vsnprintf returns -1 if output is truncated.  Increased buffer
for vsnprintf in WinConsoleFile and fmt.

1 files changed, 12 insertions, 2 deletions

diff --git a/src/fmt.cc b/src/fmt.cc
index a4e97330..5eb0979b 100644
--- a/src/fmt.cc
+++ b/src/fmt.cc
@@ -44,10 +44,20 @@ std::string fmt(const char* fmtTemplate, ...)
 {
   va_list ap;
   va_start(ap, fmtTemplate);
-  char buf[1024];
-  if(vsnprintf(buf, sizeof(buf), fmtTemplate, ap) <= 0) {
+  char buf[2048];
+  int rv;
+  rv = vsnprintf(buf, sizeof(buf), fmtTemplate, ap);
+#ifdef __MINGW32__
+  // MINGW32 vsnprintf returns -1 if output is truncated.
+  if(rv < 0 && rv != -1) {
+    // Reachable?
     buf[0] = '\0';
   }
+#else // !__MINGW32__
+  if(rv < 0) {
+    buf[0] = '\0';
+  }
+#endif // !__MINGW32__
   va_end(ap);
   return buf;
 }