According to this: sysconf(3)

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

int main(int argc, char** argv) {
    long max_user = 0;
    max_group = sysconf(_SC_NGROUPS_MAX);
    printf("Max group : %ld\n", max_group);
    return 0;
}

in the shell :

gcc -Wall -pedantic-errors -o maxgroup maxgroup.c

According to this: sysconf(3)

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

int main(int argc, char** argv) {
    long max_group = 0;
    max_group = sysconf(_SC_NGROUPS_MAX);
    printf("Max group : %ld\n", max_group);
    return 0;
}

in the shell :

gcc -Wall -pedantic-errors -o maxgroup maxgroup.c

According to this: sysconf(3)

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

int main(int argc, char** argv) {
    long max_user = 0;
    max_user = sysconf(_SC_NGROUPS_MAX);
    printf("Max user group : %ld\n", max_user);
    return 0;
}

in the shell :

gcc -Wall -pedantic-errors -o maxgroup maxgroup.c

According to this: sysconf(3)

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

int main(int argc, char** argv) {
    long max_user = 0;
    max_group = sysconf(_SC_NGROUPS_MAX);
    printf("Max group : %ld\n", max_group);
    return 0;
}

in the shell :

gcc -Wall -pedantic-errors -o maxgroup maxgroup.c