getusershell(3) Library Functions Manual getusershell(3)
NAME
getusershell, setusershell, endusershell - get permitted user shells
LIBRARY
Standard C library (libc, -lc)
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 un-
readable, 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() │ │ │
└──────────────────────────────────────────┴───────────────┴───────────┘
STANDARDS
None.
HISTORY
4.3BSD.
SEE ALSO
shells(5)
Linux man-pages 6.9.1 2024-05-02 getusershell(3)
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