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getpass(3) — Linux manual page

NAME \|LIBRARY \|SYNOPSIS \|DESCRIPTION \|RETURN VALUE \|ERRORS \|FILES \|ATTRIBUTES \|STANDARDS \|HISTORY \|NOTES \|BUGS \|SEE ALSO \|COLOPHON

getpass(3)               Library Functions Manualgetpass(3)

NAME top

       getpass - get a password

LIBRARY top

       Standard C library (libc,-lc)

SYNOPSIS top

#include <unistd.h>[[deprecated]] char *getpass(const char *prompt);   Feature Test Macro Requirements for glibc (seefeature_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 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       This function is obsolete.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 theECHO flag intermios(3).       Thegetpass() function opens/dev/tty (the controlling terminal of       the process), outputs the stringprompt, turns off echoing, reads       one line (the "password"), restores the terminal state and closes/dev/tty again.

RETURN VALUE top

       The functiongetpass() returns a pointer to a static buffer       containing (the firstPASS_MAXbytes 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 top

ENXIOThe process does not have a controlling terminal.

FILES top

/dev/tty

ATTRIBUTES top

       For an explanation of the terms used in this section, seeattributes(7).       ┌───────────────────────────────┬───────────────┬────────────────┐       │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 insteadreadpassphrase(3bsd), provided bylibbsd.       In the GNU C library implementation, if/dev/tty cannot be opened,       the prompt is written tostderr and the password is read fromstdin.  There is no limit on the length of the password.  Line       editing is not disabled.       According to SUSv2, the value ofPASS_MAXmust be defined in<limits.h> in case it is smaller than 8, and can in any case be       obtained usingsysconf(_SC_PASS_MAX).  However, POSIX.2 withdraws       the constantsPASS_MAXand_SC_PASS_MAX, and the functiongetpass().  The glibc version accepts_SC_PASS_MAXand returnsBUFSIZ(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.

COLOPHON top

       This page is part of theman-pages (Linux kernel and C library       user-space interface documentation) project.  Information about       the project can be found at        ⟨https://www.kernel.org/doc/man-pages/⟩.  If you have a bug report       for this manual page, see       ⟨https://git.kernel.org/pub/scm/docs/man-pages/man-pages.git/tree/CONTRIBUTING⟩.       This page was obtained from the tarball man-pages-6.15.tar.gz       fetched from       ⟨https://mirrors.edge.kernel.org/pub/linux/docs/man-pages/⟩ on       2025-08-11.  If you discover any rendering problems in this HTML       version of the page, or you believe there is a better or more up-       to-date source for the page, or you have corrections or       improvements to the information in this COLOPHON (which isnot       part of the original manual page), send a mail to       man-pages@man7.orgLinux man-pages 6.15            2025-05-17getpass(3)

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