getpass(3)                                            Library Functions Manual                                           getpass(3)

NAME
       getpass - get a password

LIBRARY
       Standard C library (libc, -lc)

SYNOPSIS
       #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:
               none

DESCRIPTION
       This  function is obsolete.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).

       The getpass() function opens /dev/tty (the controlling terminal of the process), outputs the string prompt, turns off  echo‐
       ing, 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 newline, terminated by a null byte ('\0').  This buffer may be overwritten by a following call.  On error,  the
       terminal state is restored, errno is set to indicate the error, and NULL is returned.

ERRORS
       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 │
       └──────────────────────────────────────────────────────────────────────────────────────────┴───────────────┴────────────────┘

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

NOTES
       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(_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)

Linux man-pages 6.03                                         2023-02-05                                                  getpass(3)