getpwuid() — Access the user database by user ID

Standards

Standards / Extensions	C or C++	Dependencies
POSIX.1 XPG4 XPG4.2 Single UNIX Specification, Version 3	both

Format

#define _POSIX_SOURCE
#include <pwd.h>

struct passwd *getpwuid(uid_t uid);

General description

Gets information about a user with the specified uid. getpwuid() returns a pointer to a passwd structure containing an entry from the user database for the specified uid. This structure (defined in the pwd.h header file), contains the following members:

pw_name: User name
pw_uid: User ID (UID) number
pw_gid: Group ID (GID) number
pw_dir: Initial working directory
pw_shell: Initial user program

Return values may point to the static data that is overwritten on each call.

Returned value

If successful, getpwuid() returns a pointer.

If unsuccessful, getpwuid() returns a NULL pointer and sets errno to one of the following values:

Error Code: Description
EMVSSAF2ERR: The system authorization facility (SAF) or RACF® Get GMAP or Get UMAP service had an error.
EMVSSAFEXTRERR: The SAF or RACF RACROUTE EXTRACT service had an error.

Example

CELEBG17

/* CELEBG17

   This example provides information for user ID 0.

 */
#define _POSIX_SOURCE
#include <sys/types.h>
#include <pwd.h>

main() {
  struct passwd *p;
  uid_t  uid=0;

  if ((p = getpwuid(uid)) == NULL)
    perror("getpwuid() error");
  else {
    printf("getpwuid() returned the following info for uid %d:\n",
           (int) uid);
    printf("  pw_name  : %s\n",       p->pw_name);
    printf("  pw_uid   : %d\n", (int) p->pw_uid);
    printf("  pw_gid   : %d\n", (int) p->pw_gid);
    printf("  pw_dir   : %s\n",       p->pw_dir);
    printf("  pw_shell : %s\n",       p->pw_shell);
  }
}

Output

getpwuid() returned the following info for uid 0:
  pw_name  : MEGA
  pw_uid   : 0
  pw_gid   : 512
  pw_dir   : /u/mega
  pw_shell : /bin/sh