linux c 获取用户组

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

int main() {
    gid_t gid = getgid();
    printf("Current GID: %d\n", gid);
    return 0;
}

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

int main() {
    int num_groups = getgroups(0, NULL);
    if (num_groups == -1) {
        perror("getgroups");
        return 1;
    }

    gid_t *groups = malloc(num_groups * sizeof(gid_t));
    if (getgroups(num_groups, groups) == -1) {
        perror("getgroups");
        free(groups);
        return 1;
    }

    printf("Groups: ");
    for (int i = 0; i < num_groups; i++) {
        printf("%d ", groups[i]);
    }
    printf("\n");

    free(groups);
    return 0;
}

#include <pwd.h>
#include <grp.h>
#include <stdio.h>

int main() {
    uid_t uid = getuid();
    struct passwd *pw = getpwuid(uid);
    if (pw == NULL) {
        perror("getpwuid");
        return 1;
    }

    gid_t gid = pw->pw_gid;
    struct group *gr = getgrgid(gid);
    if (gr == NULL) {
        perror("getgrgid");
        return 1;
    }

    printf("User: %s, Group: %s\n", pw->pw_name, gr->gr_name);
    return 0;
}