getpass(3) - Linux manual page (original) (raw)
getpass(3) Library Functions Manual getpass(3)
NAME top
getpass - get a passwordLIBRARY top
Standard C library (_libc_, _-lc_)SYNOPSIS top
**#include <unistd.h>**
**[[deprecated]] char *getpass(const char ***_prompt_**);**Feature Test Macro Requirements for glibc (see feature_test_macros(7)):
**getpass**():
Since glibc 2.2.2:
_XOPEN_SOURCE && ! (_POSIX_C_SOURCE >= 200112L)
|| /* glibc >= 2.19: */ _DEFAULT_SOURCE
|| /* glibc <= 2.19: */ _BSD_SOURCE
Before glibc 2.2.2:
noneDESCRIPTION top
This function is obsolete. Do not use it. See NOTES. If you
want to read input without terminal echoing enabled, see the
description of the _ECHO_ flag in [termios(3)](../man3/termios.3.html).
The **getpass**() function opens _/dev/tty_ (the controlling terminal of
the process), outputs the string _prompt_, turns off echoing, reads
one line (the "password"), restores the terminal state and closes
_/dev/tty_ again.RETURN VALUE top
The function **getpass**() returns a pointer to a static buffer
containing (the first **PASS_MAX** bytes of) the password without the
trailing newline, terminated by a null byte ('\0'). This buffer
may be overwritten by a following call. On error, the terminal
state is restored, _[errno](../man3/errno.3.html)_ is set to indicate the error, and NULL is
returned.ERRORS top
**ENXIO** The process does not have a controlling terminal.FILES top
_/dev/tty_ATTRIBUTES top
For an explanation of the terms used in this section, see
[attributes(7)](../man7/attributes.7.html).
┌───────────────────────────────┬───────────────┬────────────────┐
│ **Interface** │ **Attribute** │ **Value** │
├───────────────────────────────┼───────────────┼────────────────┤
│ **getpass**() │ Thread safety │ MT-Unsafe term │
└───────────────────────────────┴───────────────┴────────────────┘STANDARDS top
None.HISTORY top
Version 7 AT&T UNIX. Present in SUSv2, but marked LEGACY.
Removed in POSIX.1-2001.NOTES top
You should use instead **readpassphrase**(3bsd), provided by _libbsd_.
In the GNU C library implementation, if _/dev/tty_ cannot be opened,
the prompt is written to _stderr_ and the password is read from
_stdin_. There is no limit on the length of the password. Line
editing is not disabled.
According to SUSv2, the value of **PASS_MAX** must be defined in
_<limits.h>_ in case it is smaller than 8, and can in any case be
obtained using _sysconf(SCPASSMAX)_. However, POSIX.2 withdraws
the constants **PASS_MAX** and **_SC_PASS_MAX**, and the function
**getpass**(). The glibc version accepts **_SC_PASS_MAX** and returns
**BUFSIZ** (e.g., 8192).BUGS top
The calling process should zero the password as soon as possible
to avoid leaving the cleartext password visible in the process's
address space.SEE ALSO top
[crypt(3)](../man3/crypt.3.html)COLOPHON top
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man-pages@man7.orgLinux man-pages 6.10 2024-07-23 getpass(3)
Pages that refer to this page:crypt(3)