plan9 man page for getpass

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

NAME
       getpass - get a password

SYNOPSIS
       #include <unistd.h>

       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 since 2.19: */ _DEFAULT_SOURCE
		   || /* Glibc versions <= 2.19: */ _BSD_SOURCE
	   Before glibc 2.2.2:
	       none

DESCRIPTION
       This  function  is  obsolete.   Do not use it.  If you want to read input without terminal echoing enabled, see the description of the ECHO
       flag in termios(3).

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

ERRORS
       The function may fail if

       ENXIO  The process does not have a controlling terminal.

FILES
       /dev/tty

ATTRIBUTES
       For an explanation of the terms used in this section, see attributes(7).

       +----------+---------------+----------------+
       |Interface | Attribute	  | Value	   |
       +----------+---------------+----------------+
       |getpass() | Thread safety | MT-Unsafe term |
       +----------+---------------+----------------+
CONFORMING TO
       Present in SUSv2, but marked LEGACY.  Removed in POSIX.1-2001.

NOTES
       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(_SC_PASS_MAX).	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
       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
       crypt(3)

COLOPHON
       This  page is part of release 4.15 of the Linux man-pages project.  A description of the project, information about reporting bugs, and the
       latest version of this page, can be found at https://www.kernel.org/doc/man-pages/.

Linux								    2016-03-15								GETPASS(3)