getgroups(2) [opendarwin man page]

GETGROUPS(2)						      BSD System Calls Manual						      GETGROUPS(2)

NAME

     getgroups -- get group access list

SYNOPSIS

     #include <sys/param.h>
     #include <sys/types.h>
     #include <unistd.h>

     int
     getgroups(int gidsetlen, gid_t *gidset);

DESCRIPTION

     Getgroups() gets the current group access list of the current user process and stores it in the array gidset.  The parameter gidsetlen indi-
     cates the number of entries that may be placed in gidset.	Getgroups() returns the actual number of groups returned in gidset.  No more than
     {NGROUPS_MAX} will ever be returned.  If gidsetlen is 0, getgroups() returns the number of groups without modifying the gidset array.

RETURN VALUES

     A successful call returns the number of groups in the group set.  A value of -1 indicates that an error occurred, and the error code is
     stored in the global variable errno.

ERRORS

     The possible errors for getgroups() are:

     [EINVAL]		The argument gidsetlen is smaller than the number of groups in the group set.

     [EFAULT]		The argument gidset specifies an invalid address.

SEE ALSO

     setgroups(2), initgroups(3)

HISTORY

     The getgroups() function call appeared in 4.2BSD.

4.2 Berkeley Distribution					  April 16, 1994					 4.2 Berkeley Distribution

GETGROUPS(2)						      BSD System Calls Manual						      GETGROUPS(2)

NAME

     getgroups -- get group access list

LIBRARY

     Standard C Library (libc, -lc)

SYNOPSIS

     #include <unistd.h>

     int
     getgroups(int gidsetlen, gid_t *gidset);

DESCRIPTION

     The getgroups() system call gets the current group access list of the user process and stores it in the array gidset.  The gidsetlen argument
     indicates the number of entries that may be placed in gidset.  The getgroups() system call returns the actual number of groups returned in
     gidset.  At least one and as many as {NGROUPS_MAX}+1 values may be returned.  If gidsetlen is zero, getgroups() returns the number of supple-
     mentary group IDs associated with the calling process without modifying the array pointed to by gidset.

     The value of {NGROUPS_MAX} should be obtained using sysconf(3) to avoid hard-coding it into the executable.

RETURN VALUES

     A successful call returns the number of groups in the group set.  A value of -1 indicates that an error occurred, and the error code is
     stored in the global variable errno.

ERRORS

     The possible errors for getgroups() are:

     [EINVAL]		The argument gidsetlen is smaller than the number of groups in the group set.

     [EFAULT]		The argument gidset specifies an invalid address.

SEE ALSO

     setgroups(2), initgroups(3), sysconf(3)

STANDARDS

     The getgroups() system call conforms to IEEE Std 1003.1-2008 (``POSIX.1'').

HISTORY

     The getgroups() system call appeared in 4.2BSD.

BSD
								 January 21, 2011							       BSD