getgroups (2)

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(The comments found at the beginning of the groff file "man2/getgroups.2freebsd".)

NAME

getgroups - get group access list

LIBRARY

Lb libc

SYNOPSIS

In unistd.h Ft int Fn getgroups int gidsetlen gid_t *gidset

DESCRIPTION

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

Bq Er EINVAL

The argument Fa gidsetlen is smaller than the number of groups in the group set.

Bq Er EFAULT

The argument Fa gidset specifies an invalid address.

SEE ALSO

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

STANDARDS

The Fn getgroups system call conforms to St -p1003.1-2008 .

HISTORY

The Fn getgroups system call appeared in BSD 4.2