{"id":6657,"date":"2022-12-20T19:19:37","date_gmt":"2022-12-20T22:19:37","guid":{"rendered":"http:\/\/lode.uno\/linux-man\/index.php\/2022\/12\/20\/getgrnam-man3\/"},"modified":"2022-12-20T19:19:37","modified_gmt":"2022-12-20T22:19:37","slug":"getgrnam-man3","status":"publish","type":"post","link":"https:\/\/lode.uno\/linux-man\/2022\/12\/20\/getgrnam-man3\/","title":{"rendered":"GETGRNAM (man3)"},"content":{"rendered":"

GETGRNAM<\/h1>\n

NAME<\/a>
SYNOPSIS<\/a>
DESCRIPTION<\/a>
RETURN VALUE<\/a>
ERRORS<\/a>
FILES<\/a>
ATTRIBUTES<\/a>
CONFORMING TO<\/a>
NOTES<\/a>
SEE ALSO<\/a>
COLOPHON<\/a> <\/p>\n

\n

NAME <\/a> <\/h2>\n

getgrnam, getgrnam_r, getgrgid, getgrgid_r \u2212 get group file entry<\/p>\n

SYNOPSIS <\/a> <\/h2>\n

#include
#include <\/b><\/p>\n

struct group *getgrnam(const char *<\/b>name<\/i>);<\/b><\/p>\n

struct group *getgrgid(gid_t<\/b> gid<\/i>);<\/b><\/p>\n

int getgrnam_r(const char *<\/b>name<\/i>, struct group *<\/b>grp<\/i>,
char *<\/b>buf<\/i>, size_t<\/b> buflen<\/i>, struct group **<\/b>result<\/i>);<\/b><\/p>\n

int getgrgid_r(gid_t<\/b> gid<\/i>, struct group *<\/b>grp<\/i>,
char *<\/b>buf<\/i>, size_t<\/b> buflen<\/i>, struct group **<\/b>result<\/i>);<\/b><\/p>\n

Feature Test Macro Requirements for glibc (see feature_test_macros<\/b>(7)):<\/p>\n

getgrnam_r<\/b>(), getgrgid_r<\/b>():<\/p>\n

_POSIX_C_SOURCE
|| \/bin \/boot \/dead.letter \/dev \/etc \/home \/initrd \/lib \/lib64 \/lost+found \/media \/mnt \/opt \/proc \/release-notes.html \/release-notes.txt \/root \/run \/sbin \/srv \/sys \/tmp \/usr \/var Glibc versions <= 2.19: bodies\/ usr\/ _BSD_SOURCE || _SVID_SOURCE<\/p>\n

DESCRIPTION <\/a> <\/h2>\n

The getgrnam<\/b>() function returns a pointer to a structure containing the broken-out fields of the record in the group database (e.g., the local group file \/etc\/group<\/i>, NIS, and LDAP) that matches the group name name<\/i>.<\/p>\n

The getgrgid<\/b>() function returns a pointer to a structure containing the broken-out fields of the record in the group database that matches the group ID gid<\/i>.<\/p>\n

The group<\/i> structure is defined in <\/i> as follows:<\/p>\n

struct group {
char *gr_name; \/bin \/boot \/dead.letter \/dev \/etc \/home \/initrd \/lib \/lib64 \/lost+found \/media \/mnt \/opt \/proc \/release-notes.html \/release-notes.txt \/root \/run \/sbin \/srv \/sys \/tmp \/usr \/var group name bodies\/ usr\/
char *gr_passwd; \/bin \/boot \/dead.letter \/dev \/etc \/home \/initrd \/lib \/lib64 \/lost+found \/media \/mnt \/opt \/proc \/release-notes.html \/release-notes.txt \/root \/run \/sbin \/srv \/sys \/tmp \/usr \/var group password bodies\/ usr\/
gid_t gr_gid; \/bin \/boot \/dead.letter \/dev \/etc \/home \/initrd \/lib \/lib64 \/lost+found \/media \/mnt \/opt \/proc \/release-notes.html \/release-notes.txt \/root \/run \/sbin \/srv \/sys \/tmp \/usr \/var group ID bodies\/ usr\/
char **gr_mem; \/bin \/boot \/dead.letter \/dev \/etc \/home \/initrd \/lib \/lib64 \/lost+found \/media \/mnt \/opt \/proc \/release-notes.html \/release-notes.txt \/root \/run \/sbin \/srv \/sys \/tmp \/usr \/var NULL-terminated array of pointers
to names of group members bodies\/ usr\/
};<\/p>\n

For more information about the fields of this structure, see group<\/b>(5).<\/p>\n

The getgrnam_r<\/b>() and getgrgid_r<\/b>() functions obtain the same information as getgrnam<\/b>() and getgrgid<\/b>(), but store the retrieved group<\/i> structure in the space pointed to by grp<\/i>. The string fields pointed to by the members of the group<\/i> structure are stored in the buffer buf<\/i> of size buflen<\/i>. A pointer to the result (in case of success) or NULL (in case no entry was found or an error occurred) is stored in *result<\/i>.<\/p>\n

The call<\/p>\n

sysconf(_SC_GETGR_R_SIZE_MAX)<\/p>\n

returns either \u22121, without changing errno<\/i>, or an initial suggested size for buf<\/i>. (If this size is too small, the call fails with ERANGE<\/b>, in which case the caller can retry with a larger buffer.)<\/p>\n

RETURN VALUE <\/a> <\/h2>\n

The getgrnam<\/b>() and getgrgid<\/b>() functions return a pointer to a group<\/i> structure, or NULL if the matching entry is not found or an error occurs. If an error occurs, errno<\/i> is set appropriately. If one wants to check errno<\/i> after the call, it should be set to zero before the call.<\/p>\n

The return value may point to a static area, and may be overwritten by subsequent calls to getgrent<\/b>(3), getgrgid<\/b>(), or getgrnam<\/b>(). (Do not pass the returned pointer to free<\/b>(3).)<\/p>\n

On success, getgrnam_r<\/b>() and getgrgid_r<\/b>() return zero, and set *result<\/i> to grp<\/i>. If no matching group record was found, these functions return 0 and store NULL in *result<\/i>. In case of error, an error number is returned, and NULL is stored in *result<\/i>.<\/p>\n

ERRORS <\/a> <\/h2>\n

0<\/b> or ENOENT<\/b> or ESRCH<\/b> or EBADF<\/b> or EPERM<\/b> or …<\/p>\n

The given name<\/i> or gid<\/i> was not found.<\/p>\n\n\n\n\n\n\n\n
<\/td>\n\n

EINTR<\/b><\/p>\n<\/td>\n

<\/td>\n\n

A signal was caught; see signal<\/b>(7).<\/p>\n<\/td>\n<\/tr>\n

<\/td>\n\n

EIO<\/b><\/p>\n<\/td>\n

<\/td>\n\n

I\/O error.<\/p>\n<\/td>\n<\/tr>\n

<\/td>\n\n

EMFILE<\/b><\/p>\n<\/td>\n

<\/td>\n\n

The per-process limit on the number of open file descriptors has been reached.<\/p>\n<\/td>\n<\/tr>\n

<\/td>\n\n

ENFILE<\/b><\/p>\n<\/td>\n

<\/td>\n\n

The system-wide limit on the total number of open files has been reached.<\/p>\n<\/td>\n<\/tr>\n

<\/td>\n\n

ENOMEM<\/b><\/p>\n<\/td>\n

<\/td>\n\n

Insufficient memory to allocate group<\/i> structure.<\/p>\n<\/td>\n<\/tr>\n

<\/td>\n\n

ERANGE<\/b><\/p>\n<\/td>\n

<\/td>\n\n

Insufficient buffer space supplied.<\/p>\n<\/td>\n<\/tr>\n<\/table>\n

FILES <\/a> <\/h2>\n

\/etc\/group<\/i><\/p>\n

local group database file<\/p>\n

ATTRIBUTES <\/a> <\/h2>\n

For an explanation of the terms used in this section, see attributes<\/b>(7).<\/p>\n

\"Image<\/p>\n

CONFORMING TO <\/a> <\/h2>\n

POSIX.1-2001, POSIX.1-2008, SVr4, 4.3BSD.<\/p>\n

NOTES <\/a> <\/h2>\n

The formulation given above under “RETURN VALUE” is from POSIX.1. It does not call “not found” an error, hence does not specify what value errno<\/i> might have in this situation. But that makes it impossible to recognize errors. One might argue that according to POSIX errno<\/i> should be left unchanged if an entry is not found. Experiments on various UNIX-like systems show that lots of different values occur in this situation: 0, ENOENT, EBADF, ESRCH, EWOULDBLOCK, EPERM, and probably others.<\/p>\n

SEE ALSO <\/a> <\/h2>\n

endgrent<\/b>(3), fgetgrent<\/b>(3), getgrent<\/b>(3), getpwnam<\/b>(3), setgrent<\/b>(3), group<\/b>(5)<\/p>\n

COLOPHON <\/a> <\/h2>\n

This page is part of release 5.10 of the Linux man-pages<\/i> project. A description of the project, information about reporting bugs, and the latest version of this page, can be found at https:\/\/www.kernel.org\/doc\/man\u2212pages\/.<\/p>\n

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