#define _GNU_SOURCE
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <assert.h>
int main(int argc, char *argv[])
{
    int t[2];
    int size;
    assert(pipe(t) == 0);
    size = fcntl(t[0], F_GETPIPE_SZ);
    printf("size = %d\n", size);
    return 0;
}