How to ignore empty pipes in CHILD process?

Question

I am using a subroutine named read_from_pipe in my child process as below to read whatever is in the pipe and display it:

void read_from_pipe(int fileDescriptr)
{
    FILE *stream;
    int c;
    if (fileDesc_Is_Valid(fileDescriptr) == TRUE)
    {
        stream = fdopen(fileDescriptr, "r");
        while ((c = fgetc(stream)) != EOF)
            putchar(c);                                     
        fclose(stream);
    }
    else                                                     
        perror("Reading from pipe failed -->");
}

fileDesc_Is_Valid is another subroutine which checks the existance of file descriptor.

The problem is that because I have used waitpid(pid, &status, 0); statement in my parent to wait for child to finish off its tasks, the compiler gets stuck in the first cold run at while loop when pipe is actually empty. How can I AND another condition in my while to let compiler simply ignore empty pipes?

Answer 1

It's actually very simple, you just need to ignore the SIGPIPE signal, and it's done with a single function-call:

signal(SIGPIPE, SIG_IGN);

When the pipe is empty, instead of raising the SIGPIPE signal, reading from the pipe will return an end-of-file value (the underlying read system-call will return 0).