simple pipe program gets this error - 'Program received signal SIGPIPE, Broken pipe'

Question

I have the following code of a simple program which in it a father process sends a msg to child process with pipe

#include <unistd.h>
#include <stdio.h>

int main(){
        int file_des[2];
        pipe(file_des);
        int ret = fork ;
        if (ret == -1)
                printf("error");
        else if (ret > 0 ){ //father
                close(file_des[0]);
                printf("im the father sending msg :) \n");
                        write(file_des[1],"nadav",6*sizeof(char));
                        waitpid(ret);
        }
        else{ // son
                char buffer[256];
                close(file_des[1]);
                printf("im the son reading dads msg :) \n");
                        read(file_des[0],buffer,6*sizeof(char));
                printf("dads msg is   %s\n",buffer);

        }
}

but I get the following error (running with gdb) :

Program received signal SIGPIPE, Broken pipe.
0x00007ffff7b00870 in __write_nocancel () at ../sysdeps/unix/syscall-template.S:81
81  ../sysdeps/unix/syscall-template.S: No such file or directory.

where is the problem here ? what am I doing wrong ?

Answer 1

I guess the problem is here

int ret = fork ;

Instead of a function call like int ret = fork(); you assign a function pointer to the ret variable, which casts implicitly to int . Now your program acts like a parent process, but it didn't spawn any child actually. You close the read end of the pipe and ta da -- you write to the pipe with no readers.