字串錯誤

如果 perror 不夠靈活，你可以通過從 <string.h> 呼叫 strerror 來獲取使用者可讀的錯誤描述。

int main(int argc, char *argv[])
{
    FILE *fout;
    int last_error = 0;

    if ((fout = fopen(argv[1], "w")) == NULL) {
        last_error = errno;
         /* reset errno and continue */
         errno = 0;
    }

    /* do some processing and try opening the file differently, then */

    if (last_error) {
        fprintf(stderr, "fopen: Could not open %s for writing: %s", 
                argv[1], strerror(last_error));
        fputs("Cross fingers and continue", stderr);
    }

    /* do some other processing */

    return EXIT_SUCCESS;
}