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

       getpass - get a password

       #include <unistd.h>

       char *getpass( const char * prompt );

       This function is obsolete. Do not use it.

       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 termi-
       nal state and closes /dev/tty again.

       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 NUL.  This buffer may
       be  overwritten	by  a following call.  On error, the terminal state is restored, errno is
       set appropriately, and NULL is returned.

       The function may fail if

       ENXIO  The process does not have a controlling terminal.

       For libc4 and libc5, the prompt is not written to /dev/tty but to  stderr.   Moreover,  if
       /dev/tty  cannot be opened, the password is read from stdin.  The static buffer has length
       128 so that only the first 127 bytes of the password  are  returned.   While  reading  the
       password,  signal generation (SIGINT, SIGQUIT, SIGSTOP, SIGTSTOP) is disabled and the cor-
       responding characters (usually control-C, control-\, control-Z and control-Y)  are  trans-
       mitted  as part of the password.  Since libc 5.4.19 also line editing is disabled, so that
       also backspace and the like will be seen as part of the password.

       For glibc2, 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

       According to the 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  ().
       Libc4   and   libc5  have  never  supported  PASS_MAX  or  _SC_PASS_MAX.   Glibc2  accepts
       _SC_PASS_MAX and returns BUFSIZ (e.g., 8192).



       A getpass function appeared in Version 7 AT&T UNIX.

       The calling process should zero the password as soon as	possible  to  avoid  leaving  the
       cleartext password visible in the process's address space.

Linux Manpage				    2000-12-05				       GETPASS(3)
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