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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       This  function  is  obsolete.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 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 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).

       ┌──────────┬───────────────┬────────────────┐
       │InterfaceAttributeValue          │
       ├──────────┼───────────────┼────────────────┤
       │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

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