getgroups.2

来自「<B>Digital的Unix操作系统VAX 4.2源码</B>」· 2 代码 · 共 69 行

.\" SCCSID: @(#)getgroups.2	3.1	11/23/87
.\" Last modified by MJT on 3-Jul-86  0838
.\"  Merged RR and Jenkins changes with latest library version.  Sigh.
.\"
.TH getgroups 2
.SH Name
getgroups \- get group access list
.SH Syntax
.nf
#include <sys/types.h>
#include <unistd.h>
.PP
int getgroups(\fIgidsetsize, grouplist\fP) 
int \fIgidsetsize\fP;
int \fIgrouplist\fP[];
.fi
.SH Description
.NXR "getgroups system call"
.NXR "group access list" "getting"
The 
.PN getgroups
call gets the current group access list of the user process
and stores it in the array of int 
.IR grouplist .
The 
.I gidsetsize
parameter indicates the number of entries that can be placed in 
.IR grouplist .
.SH Return Values
Upon success, the call returns the 
number of groups as the value of the function.
No more than NGROUPS, as defined in <sys/param.h>, are
returned.
.PP
A value of \-1 indicates that an error occurred, and the error
code is stored in the global variable, \fIerrno\fP\|.
.SH Diagnostics
The 
.PN getgroups
call fails under the following conditions: 
.TP 15
[EINVAL]
The 
.I gidsetsize
argument is smaller than the number of groups in the group set.
.TP 15
[EFAULT]
The \fIgrouplist\fP argument specifies
invalid addresses.
.SH Environment
.SS POSIX
When your program is compiled in the POSIX environment, the
.IR grouplist
argument should be defined as follows:
.sp
.ft B
gid_t	grouplist[];
.PP
Additionally, in the POSIX environment, if the 
.IR gidsetsize 
argument is zero,
.PN getgroups
returns the number of supplemental group IDs associated with 
the calling process, without modifying the array pointed to by the 
.IR grouplist
argument.
.SH See Also
setgroups(2), initgroups(3x)