检查输入以查看用户是否输入了control -d

Question

Pretty new to C, and I have what may be a pretty simple question. I am writing a program in C which reads a series of strings from the user. The program is supposed to do something with these strings after the user indicates that he is done entering strings. He does this by entering "Ctrl-D".

I'm having trouble figuring out how to check if the user has entered "Ctrl-D". From my initial research, it appears as though Ctrl-D is supposed to have something to do with End of File, which, it appears is not a character that I can easily check against.

I'm trying to read these strings via scanf. I have the following code (please ignore the initial strings array that eventually get returned. I know it does nothing at the moment.

char **get_fragments_from_user(){
    char *strings[20000];

    char tempstring[1001];
    while(true){
        printf("\n> ");
        scanf("%s", &tempstring);
        printf("\n Recorded %s", tempstring);
        if(tempstring[0] == -1) break;
    }
    return strings;
}

Is there an easy way to check to see if the user has entered 'Ctrl-D'?

Answer 1

Never use scanf .

If you have getline , use that. Otherwise, use fgets . Either way, a typed Ctrl-D (or end-of-file from redirected input) will be passed up to you as zero characters read , ie an empty string. (If the user just presses Return without typing anything first, you get the one -character string "\\n".)