Dear Monks,

I need to setup a communication link between a C program and a perl program. This C program executes the perl script and reads the output from the perl script. This perl script writes its output to a file-descriptor
#! /usr/bin/perl
open OUT ,">&63" ;

print OUT "this is a message\n" ;

close OUT  ;

[download]
At the end of this post I've attached the C program.
Anyway, this doesn't work at all. However, when I use 0 instead of 63, everything works fine!!

Any suggestions what I'm doing wrong here with the file-descriptor 63 ?

Thnx a lot
LuCa

C program:
#include <unistd.h>
#include <stdio.h>
#include <fcntl.h>

main()
{
    const int RESPONSE_FD = 63;
    int pfd[2], status, size;
    char buffer[100];

    status = pipe(pfd);
    if(status == -1)
    {
        printf("Could not open pipe\n");
        exit(1);
    }
    else
    {
        printf("The filedescriptors are: %d %d\n", pfd[0], pfd[1]);
    }

    status = fork();
    if(status == 0)
    {
        printf("This is the child\n");
        status = dup2(pfd[0], RESPONSE_FD);
        if(status == -1)
        {
            printf("dup2 failed\n");
            exit(1);
        }
        close(pfd[1]);
        close(pfd[0]);
        while(read(STDIN_FILENO, buffer, sizeof(buffer))>0)
        {
            printf("%s", buffer);
        }
    }
    else
    {
        printf("This is the parent\n");
        system("my_prog.pl");
    }
}

[download]

In reply to communication between C and perl by jeanluca

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