NAME

       user_from_uid, uid_from_user, group_from_gid, gid_from_group — cache password and group entries

LIBRARY

       Utility functions from BSD systems (libbsd, -lbsd)

SYNOPSIS

       #include <pwd.h>
       (See libbsd(7) for include usage.)

       int
       uid_from_user(const char *name, uid_t *uid);

       const char *
       user_from_uid(uid_t uid, int nouser);

       #include <grp.h>

       int
       gid_from_group(const char *name, gid_t *gid);

       const char *
       group_from_gid(gid_t gid, int nogroup);

DESCRIPTION

       The  user_from_uid()  function  returns the user name associated with the argument uid.  The user name is
       cached so that multiple calls with the same uid do not require additional calls to getpwuid(3).  If there
       is no user associated with the uid, a pointer is returned to a string representation of the  uid,  unless
       the argument nouser is non-zero, in which case a null pointer is returned.

       The  uid_from_user()  function  returns  the  user  ID associated with the argument name.  The user ID is
       cached so that multiple calls with the same name do not require  additional  calls  to  getpwnam(3).   If
       there  is  no  user  ID  associated  with the name, the uid_from_user() function returns -1; otherwise it
       stores the user ID at the location pointed to by uid and returns 0.

       The group_from_gid() function returns the group name associated with the argument gid.  The group name is
       cached so that multiple calls with the same gid do not require additional calls to getgrgid(3).  If there
       is no group associated with the gid, a pointer is returned to a string representation of the gid,  unless
       the argument nogroup is non-zero, in which case a null pointer is returned.

       The  gid_from_group()  function  returns the group ID associated with the argument name.  The group ID is
       cached so that multiple calls with the same name do not require  additional  calls  to  getgrnam(3).   If
       there  is  no  group  ID associated with the name, the gid_from_group() function returns -1; otherwise it
       stores the group ID at the location pointed to by gid and returns 0.

SEE ALSO

       getgrgid(3), getpwuid(3)

HISTORY

       The user_from_uid() and group_from_gid() functions first appeared in 4.4BSD.

       The uid_from_user() and gid_from_group() functions first appeared in NetBSD 1.4 and OpenBSD 6.4.

Debian                                         September 13, 2018                               user_from_uid(3)