GETGRNAM(3P) POSIX Programmer's Manual GETGRNAM(3P)
PROLOG
This manual page is part of the POSIX Programmer's Manual. The Linux implementation of this interface may differ (consult the correspond-
ing Linux manual page for details of Linux behavior), or the interface may not be implemented on Linux.
NAME
getgrnam, getgrnam_r - search group database for a name
SYNOPSIS
#include <grp.h>
struct group *getgrnam(const char *name);
int getgrnam_r(const char *name, struct group *grp, char *buffer,
size_t bufsize, struct group **result);
DESCRIPTION
The getgrnam() function shall search the group database for an entry with a matching name.
The getgrnam() function need not be reentrant. A function that is not required to be reentrant is not required to be thread-safe.
The getgrnam_r() function shall update the group structure pointed to by grp and store a pointer to that structure at the location pointed
to by result. The structure shall contain an entry from the group database with a matching gid or name. Storage referenced by the group
structure is allocated from the memory provided with the buffer parameter, which is bufsize bytes in size. The maximum size needed for this
buffer can be determined with the {_SC_GETGR_R_SIZE_MAX} sysconf() parameter. A NULL pointer is returned at the location pointed to by
result on error or if the requested entry is not found.
RETURN VALUE
The getgrnam() function shall return a pointer to a struct group with the structure defined in <grp.h> with a matching entry if one is
found. The getgrnam() function shall return a null pointer if either the requested entry was not found, or an error occurred. On error,
errno shall be set to indicate the error.
The return value may point to a static area which is overwritten by a subsequent call to getgrent(), getgrgid(), or getgrnam().
If successful, the getgrnam_r() function shall return zero; otherwise, an error number shall be returned to indicate the error.
ERRORS
The getgrnam() and getgrnam_r() functions may fail if:
EIO An I/O error has occurred.
EINTR A signal was caught during getgrnam().
EMFILE {OPEN_MAX} file descriptors are currently open in the calling process.
ENFILE The maximum allowable number of files is currently open in the system.
The getgrnam_r() function may fail if:
ERANGE Insufficient storage was supplied via buffer and bufsize to contain the data to be referenced by the resulting group structure.
The following sections are informative.
EXAMPLES
None.
APPLICATION USAGE
Applications wishing to check for error situations should set errno to 0 before calling getgrnam(). If errno is set on return, an error
occurred.
The getgrnam_r() function is thread-safe and shall return values in a user-supplied buffer instead of possibly using a static data area
that may be overwritten by each call.
RATIONALE
None.
FUTURE DIRECTIONS
None.
SEE ALSO
endgrent(), getgrgid(), the Base Definitions volume of IEEE Std 1003.1-2001, <grp.h>, <limits.h>, <sys/types.h>
COPYRIGHT
Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1, 2003 Edition, Standard for Information Technol-
ogy -- Portable Operating System Interface (POSIX), The Open Group Base Specifications Issue 6, Copyright (C) 2001-2003 by the Institute of
Electrical and Electronics Engineers, Inc and The Open Group. In the event of any discrepancy between this version and the original IEEE
and The Open Group Standard, the original IEEE and The Open Group Standard is the referee document. The original Standard can be obtained
online at http://www.opengroup.org/unix/online.html .
IEEE
/The Open Group 2003 GETGRNAM(3P)