The hard limit of the file descriptors that can be opened by this process will become

#include<stdio.h>
#include<sys/time.h>
#include<sys/resource.h>
 
int main()
{
    struct rlimit limit;
    limit.rlim_cur = 10;
    limit.rlim_max = 20;
    if(setrlimit(RLIMIT_NOFILE,&limit) != 0)
        perror("setrlimit");
    if(getrlimit(RLIMIT_NOFILE,&limit) != 0)
        perror("getrlimit");
    printf("%lu\n",limit.rlim_cur);
    printf("%lu\n",limit.rlim_max);
    return 0;
}