fd.c file descriptor limit checker

fd.c

#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <stdio.h>

int main()
{
  int i = 0;
  while (i < 66000) {
    int fd = open("file.txt", O_RDONLY);
    printf("fd = %d\n", fd);
    if (fd == -1) {
      return 0;
    }
    i++;
  }
  return 0;
}

It may looks useless but it is actually very useful to check the number of authorized file descriptors to open in the current context.

cc fd.c && ./a,out

This will print the maximum number.