#include int main(int argc, char** argv) { FILE *fp; int i; char * output = "/tmp/io-test.txt"; if(argc == 2){ output = argv[1]; }else if(argc > 2){ printf("usage: %s [output]", argv[0]); return 100; } fp = fopen(output, "w+"); if(fp == NULL){ printf("Can't open %s", output); return 1; } i = fprintf(fp, "%s works.\n", "fprintf"); if(i <= 0){ fclose(fp); printf("Can't write 'fprintf works.' to %s (fprintf returned %d)", output, i); return 2; } i = fputs("fputs works.\n", fp); if(i == EOF){ fclose(fp); printf("Can't write 'fputs works.' to %s (fputs returned EOF)", output); return 3; } fclose(fp); return 0; }