getusershell(3)

1getusershell(3)            Library Functions Manual            getusershell(3)
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NAME

6       getusershell, setusershell, endusershell - get permitted user shells
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LIBRARY

9       Standard C library (libc, -lc)
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SYNOPSIS

12       #include <unistd.h>
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14       char *getusershell(void);
15       void setusershell(void);
16       void endusershell(void);
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18   Feature Test Macro Requirements for glibc (see feature_test_macros(7)):
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20       getusershell(), setusershell(), endusershell():
21           Since glibc 2.21:
22               _DEFAULT_SOURCE
23           In glibc 2.19 and 2.20:
24               _DEFAULT_SOURCE || (_XOPEN_SOURCE && _XOPEN_SOURCE < 500)
25           Up to and including glibc 2.19:
26               _BSD_SOURCE || (_XOPEN_SOURCE && _XOPEN_SOURCE < 500)
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DESCRIPTION

29       The  getusershell()  function  returns  the  next  line  from  the file
30       /etc/shells, opening the file if necessary.  The  line  should  contain
31       the  pathname  of a valid user shell.  If /etc/shells does not exist or
32       is unreadable, getusershell() behaves as if /bin/sh and  /bin/csh  were
33       listed in the file.
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35       The setusershell() function rewinds /etc/shells.
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37       The endusershell() function closes /etc/shells.
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RETURN VALUE

40       The getusershell() function returns NULL on end-of-file.
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FILES

43       /etc/shells
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ATTRIBUTES

46       For  an  explanation  of  the  terms  used  in  this  section,  see at‐
47       tributes(7).
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49       ┌──────────────────────────────────────────┬───────────────┬───────────┐
50       │Interface                                 │ Attribute     │ Value     │
51       ├──────────────────────────────────────────┼───────────────┼───────────┤
52       │getusershell(), setusershell(),           │ Thread safety │ MT-Unsafe │
53       │endusershell()                            │               │           │
54       └──────────────────────────────────────────┴───────────────┴───────────┘
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STANDARDS

57       None.
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HISTORY

60       4.3BSD.
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