rtprio.c

#include <stdio.h>        /* fputs, printf, puts, stderr */
#include <stdlib.h>       /* EXIT_FAILURE, EXIT_SUCCESS, exit */
#include <sys/resource.h> /* RLIM_INFINITY, RLIMIT_RTPRIO, getrlimit, setrlimit, struct rlimit */
#include <unistd.h>       /* pause */

int main(void) {
	struct rlimit rtprio;

	if (getrlimit(RLIMIT_RTPRIO, &rtprio)) {
		fputs("failed to get cur/soft rtprio\n", stderr);
		exit(EXIT_FAILURE);
	}

	printf("cur: %lu\nmax: %lu\n", rtprio.rlim_cur, rtprio.rlim_max);

	if (rtprio.rlim_cur == RLIM_INFINITY) {
		puts("cur/soft is already unlimited");
		return EXIT_SUCCESS;
	}

	if (rtprio.rlim_max != RLIM_INFINITY) {
		fputs(
		    "please add \"* hard rtprio unlimited\" to /etc/security/limits.conf\n",
		    stderr);
		exit(EXIT_FAILURE);
	}

	rtprio.rlim_cur = RLIM_INFINITY;
	if (setrlimit(RLIMIT_RTPRIO, &rtprio)) {
		fputs("failed to set cur/soft rtprio to unlimited\n", stderr);
		exit(EXIT_FAILURE);
	}

	puts("raised cur/soft rtprio successfully");
	pause();

	return EXIT_SUCCESS;
}