Add a snprintf_safe() helper function

Returns true on success or false on error _or_ truncation. Since truncation is
almost always an error anyway, we might as well make this easier to check.

Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>

1 files changed, 15 insertions, 0 deletions

diff --git a/src/utils.h b/src/utils.h
index 2c35a87..abeaabd 100644
--- a/src/utils.h
+++ b/src/utils.h
@@ -26,6 +26,7 @@
 
 #include <errno.h>
 #include <inttypes.h>
+#include <stdarg.h>
 #include <stdbool.h>
 #include <stdio.h>
 #include <string.h>
@@ -290,4 +291,18 @@ int vasprintf(char **strp, const char *fmt, va_list ap);
 # endif /* !HAVE_VASPRINTF */
 #endif /* !HAVE_ASPRINTF */
 
+static inline bool
+ATTR_PRINTF(3, 4)
+snprintf_safe(char *buf, size_t sz, const char *format, ...)
+{
+    va_list ap;
+    int rc;
+
+    va_start(ap, format);
+    rc = vsnprintf(buf, sz, format, ap);
+    va_end(ap);
+
+    return rc >= 0 && (size_t)rc < sz;
+}
+
 #endif /* UTILS_H */