libc: implement err/warn functions

1 files changed, 16 insertions, 0 deletions

diff --git a/lib/libc/err/vwarn.c b/lib/libc/err/vwarn.c
new file mode 100644
index 00000000..2f485d93
--- /dev/null
+++ b/lib/libc/err/vwarn.c
@@ -0,0 +1,16 @@
+#include <stdarg.h>
+#include <stdio.h>
+
+extern char *__progname;
+
+void vwarn(const char *fmt, va_list args)
+{
+	fprintf(stderr, "%s: ", __progname);
+
+	if (fmt != NULL) {
+		vfprintf(stderr, fmt, args);
+		fprintf(stderr, ": ");
+	}
+
+	perror(NULL);
+}