1GETPASS(3)                 Linux Programmer's Manual                GETPASS(3)
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NAME

6       getpass - get a password
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SYNOPSIS

9       #include <unistd.h>
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11       char *getpass( const char * prompt );
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DESCRIPTION

14       This function is obsolete. Do not use it.
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16       The  getpass() function opens /dev/tty (the controlling terminal of the
17       process), outputs the string prompt, turns off echoing, reads one  line
18       (the  "password"),  restores  the  terminal  state  and closes /dev/tty
19       again.
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RETURN VALUE

22       The function getpass() returns a pointer to a static buffer  containing
23       the  (first  PASS_MAX  bytes of) the password without the trailing new‐
24       line, terminated by a null byte ('\0').  This buffer may be overwritten
25       by  a  following call.  On error, the terminal state is restored, errno
26       is set appropriately, and NULL is returned.
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ERRORS

29       The function may fail if
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31       ENXIO  The process does not have a controlling terminal.
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NOTES

34       For libc4 and libc5, the prompt is  not  written  to  /dev/tty  but  to
35       stderr.   Moreover,  if /dev/tty cannot be opened, the password is read
36       from stdin.  The static buffer has length 128 so that  only  the  first
37       127  bytes  of  the password are returned.  While reading the password,
38       signal generation (SIGINT, SIGQUIT, SIGSTOP, SIGTSTOP) is disabled  and
39       the  corresponding  characters (usually control-C, control-\, control-Z
40       and control-Y) are transmitted as part of  the  password.   Since  libc
41       5.4.19  also  line  editing is disabled, so that also backspace and the
42       like will be seen as part of the password.
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44       For glibc2, if /dev/tty cannot be opened,  the  prompt  is  written  to
45       stderr  and  the password is read from stdin.  There is no limit on the
46       length of the password.  Line editing is not disabled.
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48       According to the SUSv2, the value of PASS_MAX must be defined in  <lim‐
49       its.h>  in  case  it is smaller than 8, and can in any case be obtained
50       using sysconf(_SC_PASS_MAX).  However, POSIX.2 withdraws the  constants
51       PASS_MAX and _SC_PASS_MAX, and the function getpass().  Libc4 and libc5
52       have  never  supported  PASS_MAX  or  _SC_PASS_MAX.    Glibc2   accepts
53       _SC_PASS_MAX and returns BUFSIZ (e.g., 8192).
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FILES

56       /dev/tty
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SEE ALSO

59       crypt(3)
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HISTORY

62       A getpass() function appeared in Version 7 AT&T UNIX.
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CONFORMING TO

65       Present in SUSv2, but marked LEGACY.  Removed in POSIX.1-2001.
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BUGS

68       The  calling  process  should  zero the password as soon as possible to
69       avoid leaving the cleartext password visible in the  process's  address
70       space.
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74Linux Manpage                     2000-12-05                        GETPASS(3)
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