January 6, 2005 GETGROUPLIST 3

### NAME

getgrouplist, getgroupmembership, - calculate group access list

### LIBRARY

Standard C Library (libc, -lc)

### SYNOPSIS

```int` getgrouplist(```const char *name``, gid_t basegid``, gid_t *groups``, int *ngroups`)
```int` getgroupmembership(```const char *name``, gid_t basegid``, gid_t *groups``, int maxgrp``, int *ngroups`)

### DESCRIPTION

The getgrouplist(``) and getgroupmembership(``) functions read through the group database and calculate the group access list for the user specified in ```name`. The ```basegid` is automatically included in the groups list. Typically this value is given as the group number from the password database.

The resulting group list is returned in the integer array pointed to by ```groups`.

For getgrouplist(``), the caller specifies the size of the ```groups` array in the integer pointed to by ```ngroups`.

For getgroupmembership(``), the caller specifies the size of the ```groups` array in ```maxgrp`.

The actual number of groups found is returned in ```ngroups`.

Duplicate group ids will be suppressed from the result.

### RETURN VALUES

The getgrouplist(``) and getgroupmembership(``) functions return 0 if successful, and return -1 if the size of the group list is too small to hold all the user's groups. In the latter case, the ```groups` array will be filled with as many groups as will fit and ```ngroups` will contain the total number of groups found.

### FILES

```/etc/group`
  group membership list

### SEE ALSO

setgroups(2), initgroups(3), group(5)

### HISTORY

The getgrouplist(``) function first appeared in 4.4BSD. The getgroupmembership(``) function first appeared in NetBSD3.0 to address an API deficiency in getgrouplist(``).

### BUGS

The getgrouplist(``) function uses the routines based on getgrent(3). If the invoking program uses any of these routines, the group structure will be overwritten in the call to getgrouplist(``).