diff --git a/src/test.c b/src/test.c
index 092beb2..bbae8b3 100644
--- a/src/test.c
+++ b/src/test.c
@@ -22,7 +22,7 @@ static void usage(int argc, char **argv, const char *message, ...) {
     exit(1);
 }
 
-static uint8_t *buf_malloc(png_t *png) {
+static inline uint8_t *buf_malloc(png_t *png) {
     return malloc(4 * png->width * png->height);
 }