1 files changed, 5 insertions, 0 deletions
diff --git a/src/output.c b/src/output.c
index 0d8341c..77bda63 100644
--- a/src/output.c
+++ b/src/output.c
@@ -21,6 +21,7 @@
 
 #include "output.h"
 
+#include <assert.h>
 #include <stdarg.h>
 #include <stdio.h>
 
@@ -31,6 +32,8 @@ static const char *_program_name;
 void
 set_program_name(const char *name)
 {
+	assert(name && *name);
+
 	_program_name = name;
 }
 
@@ -39,6 +42,8 @@ error(const char *format, ...)
 {
 	va_list ap;
 
+	assert(format);
+
 	fprintf(stderr, _("%s: Error: "), _program_name);
 	va_start(ap, format);
 	vfprintf(stderr, format, ap);