getgroups(2) [freebsd man page]

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

Check Out this Related Man Page

SETGROUPS(2)						      BSD System Calls Manual						      SETGROUPS(2)

NAME

     setgroups -- set group access list

LIBRARY

     Standard C Library (libc, -lc)

SYNOPSIS

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

     int
     setgroups(int ngroups, const gid_t *gidset);

DESCRIPTION

     setgroups() sets the group access list of the current user process according to the array gidset.	The parameter ngroups indicates the number
     of entries in the array and must be no more than {NGROUPS_MAX}.

     Only the super-user may set new groups.

     This system call affects only secondary groups.

RETURN VALUES

     A 0 value is returned on success, -1 on error, with an error code stored in errno.

ERRORS

     The setgroups() call will fail if:

     [EINVAL]		The value of ngroups is greater than {NGROUPS_MAX}.

     [EPERM]		The caller is not the super-user.

     [EFAULT]		The address specified for gidset is outside the process address space.

SEE ALSO

     getgroups(2), setegid(2), setgid(2), setregid(2), initgroups(3)

HISTORY

     The setgroups() function call appeared in 4.2BSD.

BSD
								  October 7, 2006							       BSD

Linux and UNIX Man Pages

getgroups(2) [freebsd man page]

Check Out this Related Man Page