linux-pam里提供了一个简单的pam应用示例：check_user

#include <security/pam_appl.h>
#include <security/pam_misc.h>
#include <stdio.h>static struct pam_conv conv = {misc_conv,NULL
};int main(int argc, char *argv[])
{pam_handle_t *pamh=NULL;int retval;const char *user="nobody";if(argc == 2) {user = argv[1];}if(argc > 2) {fprintf(stderr, "Usage: check_user [username]\n");exit(1);}retval = pam_start("check", user, &conv, &pamh);if (retval == PAM_SUCCESS)retval = pam_authenticate(pamh, 0);    /* is user really user? */if (retval == PAM_SUCCESS)retval = pam_acct_mgmt(pamh, 0);       /* permitted access? *//* This is where we have been authorized or not. */if (retval == PAM_SUCCESS) {fprintf(stdout, "Authenticated\n");