vperror implementation

This allows us to provide much more useful error messages for
syscalls.

1 files changed, 15 insertions, 0 deletions

diff --git a/util.h b/util.h
index 9af886d..b89d15e 100644
--- a/util.h
+++ b/util.h
@@ -11,3 +11,18 @@ bool safe_strtoull(const char *str, uint64_t *out);
 bool safe_strtoll(const char *str, int64_t *out);
 bool safe_strtoul(const char *str, uint32_t *out);
 bool safe_strtol(const char *str, int32_t *out);
+
+#ifdef __GCC
+# define __gcc_attribute__ __attribute__
+#else
+# define __gcc_attribute__(x)
+#endif
+
+/**
+ * Vararg variant of perror that makes for more useful error messages
+ * when reporting with parameters.
+ *
+ * @param fmt a printf format
+ */
+void vperror(const char *fmt, ...)
+    __gcc_attribute__ ((format (printf, 1, 2)));