return nonzero if any writes failed

mm/mm.c

@@ -244,12 +244,10 @@ usage(char *s){
 
 int main(int argc, char *argv[]){
 	int c;
-	FILE *f;
 	size_t i;
 	struct Io io[2]; /* {read, write, error} */
 	struct Io_ex io_ex[2];
-	FILE *lf;
-	char *ln;
+	int o;
 	char unbuffered;
 
 	if(argc < 2){ /* simple invocation */
@@ -323,18 +321,18 @@ int main(int argc, char *argv[]){
 		io[0].s = 1;
 	if(io[1].s == -1)
 		io[1].s = 1;
+	o = io[1].s;
 
-	lf = NULL;
-	
 	for(i = 0; i < io[0].s; ++i){
 		while((c = getc(io[0].files[i])) != EOF)
 			if(Io_fputc(&io[1], c) == EOF){ /* notebook's full */
 				terminate(io);
-				return EX_OK;
+				return 1;
 			}
 	}
 
+	o = io[1].s == o;
 	terminate(io);
 
-	return EX_OK;
+	return o;
 }