check printf call for error codes

Makefile

@@ -1,4 +1,4 @@
-gaycat:
+gaycat: gaycat.c
 	$(CC) -O2 -o gaycat gaycat.c
 
 install: gaycat

gaycat.c

@@ -35,32 +35,39 @@ const char *colors[NUM_COLORS] = {
 
 char buf[4096];
 
-void print_line(const char *line)
+int print_line(const char *line)
 {
 	static int color = 0;
-	printf("%s%s", colors[color], line);
+	int ret = printf("%s%s", colors[color], line);
 	if (++color == NUM_COLORS)
 		color = 0;
+	return ret;
 }
 
 int main(int argc, char *argv[])
 {
 	char *line;
 	FILE *stream;
+	int err;
+
 	if (argc < 2 || !strcmp(argv[1], "-"))
 		stream = stdin;
 	else
 		stream = fopen(argv[1], "r");
 
 	if (!stream) {
-		perror(argv[0]);
+		perror(argv[1]);
 		return 1;
 	}
 
 	while (1) {
 		line = fgets(buf, sizeof(buf), stream);
 		if (line) {
-			print_line(line);
+			err = print_line(line);
+			if (err < 0) {
+				perror(argv[0]);
+				return 3;
+			}
 		} else {
 			printf("\x1b[0m"); /* reset colors */
 			if (errno) {