getusershell(3) — Linux manual page

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 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()                    │               │           │
       └───────────────────────────────────┴───────────────┴───────────┘

STANDARDS

       None.

HISTORY

       4.3BSD.

SEE ALSO

       shells(5)

COLOPHON

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Linux man-pages 6.9.1          2024-05-02                getusershell(3)

Pages that refer to this page: shells(5)

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