CODEWITHSUNDEEP
c
Sobiaholic
Sobiaholic

Reputation: 2967

Program not terminating before forking

I'm trying to build a simple C program, it basically asks for a file name to read or \0 to terminate the program.

My problem is when I input \0 it does not terminate, instead it keeps creating the fork and executing the other c program as child, any idea why?

int main (void)
{
    printf("%d: Parent process ...\n",getpid());
    char fileName[200];

    printf ("%d: Enter an argument (or \\0 for none): ", getpid());
    fflush(stdout);
    scanf("%c", &fileName);

    if(fileName == "\\0"){
        exit(0);
    }

    int pid;
    pid = fork();

    if (pid == 0) {
        printf("%d child\n",getpid());
        execl ("./catter","catter", fileName,NULL);
    }
    sleep(6);
}

Upvotes: 0

Views: 56

Answers (1)

Yu Hao
Yu Hao

Reputation: 122503

Your program has at least two problems, the first is %c in scanf() is used for single char, not a string, you should use %s instead, or better, use fgets() for this job.

fgets(fileName, sizeof(fileName), stdin);

The second is that you are using == to compare strings, if(fileName == "\\0") would NEVER be true. strcmp() is the function you are looking for:

if (strcmp(fileName, "\\0") == 0)

Upvotes: 2

Related Questions