diff --git a/src/firejail/fs_var.c b/src/firejail/fs_var.c
index 9452d162d..11e9eabf5 100644
--- a/src/firejail/fs_var.c
+++ b/src/firejail/fs_var.c
@@ -326,7 +326,8 @@ void fs_var_utmp(void) {
 	endutent();
 
 	// save new utmp file
-	fwrite(&u_boot, sizeof(u_boot), 1, fp);
+	int rv = fwrite(&u_boot, sizeof(u_boot), 1, fp);
+	(void) rv;
 	SET_PERMS_STREAM(fp, 0, utmp_group, S_IRUSR | S_IWRITE | S_IRGRP | S_IWGRP | S_IROTH);
 	fclose(fp);
 
diff --git a/src/ftee/main.c b/src/ftee/main.c
index 2628a77c5..6aede324c 100644
--- a/src/ftee/main.c
+++ b/src/ftee/main.c
@@ -129,7 +129,8 @@ static void log_write(const unsigned char *str, int len, const char *fname) {
 		out_cnt = len;
 	}
 
-	fwrite(str, len, 1, out_fp);
+	int rv = fwrite(str, len, 1, out_fp);
+	(void) rv;
 	fflush(0);
 }
 
@@ -230,7 +231,8 @@ int main(int argc, char **argv) {
 		if (n <= 0)
 			break;
 
-		fwrite(buf, n, 1, stdout);
+		int rv = fwrite(buf, n, 1, stdout);
+		(void) rv;
 		log_write(buf, n, fname);
 	}