GETUSERSHELL(3)		   Linux Programmer's Manual	       GETUSERSHELL(3)



NAME
       getusershell, setusershell, endusershell - get permitted user shells

SYNOPSIS
       #include <unistd.h>

       char *getusershell(void);

       void setusershell(void);

       void endusershell(void);

   Feature Test Macro Requirements for glibc (see feature_test_macros(7)):

       getusershell(), setusershell(), endusershell():
	   Since glibc 2.21:
	       _DEFAULT_SOURCE
	   In glibc 2.19 and 2.20:
	       _DEFAULT_SOURCE || (_XOPEN_SOURCE && _XOPEN_SOURCE < 500)
	   Up to and including glibc 2.19:
	       _BSD_SOURCE || (_XOPEN_SOURCE && _XOPEN_SOURCE < 500)

DESCRIPTION
       The  getusershell()  function  returns  the  next  line	from  the file
       /etc/shells, opening the file if necessary.  The	 line  should  contain
       the  pathname  of a valid user shell.  If /etc/shells does not exist or
       is unreadable, getusershell() behaves as if /bin/sh and	/bin/csh  were
       listed in the file.

       The setusershell() function rewinds /etc/shells.

       The endusershell() function closes /etc/shells.

RETURN VALUE
       The getusershell() function returns NULL on end-of-file.

FILES
       /etc/shells

ATTRIBUTES
       For   an	  explanation	of   the  terms	 used  in  this	 section,  see
       attributes(7).

       +--------------------------------+---------------+-----------+
       |Interface			| Attribute	| Value	    |
       +--------------------------------+---------------+-----------+
       |getusershell(), setusershell(), | Thread safety | MT-Unsafe |
       |endusershell()			|		|	    |
       +--------------------------------+---------------+-----------+
CONFORMING TO
       4.3BSD.

SEE ALSO
       shells(5)

COLOPHON
       This page is part of release 4.10 of the Linux  man-pages  project.   A
       description  of	the project, information about reporting bugs, and the
       latest	 version    of	  this	  page,	   can	   be	  found	    at
       https://www.kernel.org/doc/man-pages/.



GNU				  2016-03-15		       GETUSERSHELL(3)