#include <stdio.h>
#include <stdlib.h>
int main(int argc, char **argv) {
    if(argc != 3) {
        fprintf(stderr, "do-not-close-stderr 'output string' 'output file'\n");
        exit(EXIT_FAILURE);
    }
    FILE *fp = fopen(argv[2], "w");
    if(!fp) {
        perror("fopen");
        exit(EXIT_FAILURE);
    }
    fprintf(stderr, "Some kind of warning message.\n");
    fprintf(fp, argv[1]);
    fprintf(fp, "\n");
    fclose(fp);
    exit(EXIT_SUCCESS);
}