GETGRNAM(P) GETGRNAM(P)
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 reen-
trant 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 con-
tain 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 Technology -- 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 orig-
inal Standard can be obtained online at http://www.opengroup.org/unix/online.html .
POSIX 2003 GETGRNAM(P)
|