The GNU C Library - Scanning All Groups

Scanning the List of All Groups

This section explains how a program can read the list of all groups in the system, one group at a time. The functions described here are declared in `grp.h'.

You can use the fgetgrent function to read group entries from a particular file.

Function struct group * fgetgrent (FILE *stream)

The fgetgrent function reads the next entry from stream. It returns a pointer to the entry. The structure is statically allocated and is rewritten on subsequent calls to fgetgrent . You must copy the contents of the structure if you wish to save the information.

The stream must correspond to a file in the same format as the standard group database file.

The way to scan all the entries in the group database is with setgrent , getgrent , and endgrent .

Function void setgrent (void)

This function initializes a stream for reading from the group data base. You use this stream by calling getgrent .

Function struct group * getgrent (void)

The getgrent function reads the next entry from the stream initialized by setgrent . It returns a pointer to the entry. The structure is statically allocated and is rewritten on subsequent calls to getgrent . You must copy the contents of the structure if you wish to save the information.

Function void endgrent (void)

This function closes the internal stream used by getgrent .