ttyslot.3

操作系统设计与实现源码

.TH TTYSLOT 3
.SH NAME
ttyslot, fttyslot \- utmp slot number
.SH SYNOPSIS
.nf
.ft B
#define _MINIX_SOURCE 1
#include <unistd.h>

int ttyslot(void)
int fttyslot(int \fIfd\fP)
.fi
.ft P
.SH DESCRIPTION
.B Ttyslot()
returns the index of the login terminal in the
.B utmp
file.  It tries
.B fttyslot()
on file descriptors
.BR 0,
.BR 1,
and
.BR 2
to find the index.
.PP
.B Fttyslot()
returns the utmp index of the terminal associated with file descriptor
.IR fd .
First it tries to map
.I fd
to a terminal name with
.BR ttyname (3),
then it searches the
.BR ttytab (5)
database with the
.BR getttyent (3)
function for this terminal.  This means that the utmp slot number is the
same as the ttytab entry number counting from 1.  The value 0 is returned if
no slot number can be found for a file descriptor.
.SH "SEE ALSO"
.BR ttyname (3),
.BR getttyent (3),
.BR utmp (5),
.BR ttytab (5),
.BR init (8).
.SH NOTES
Since 0 is used as an error return this means that the first entry in the
utmp file is not used.
.PP
.B Ttyslot()
is often found in a UNIX implementation,
.B fttyslot()
is Minix specific.
.SH AUTHOR
Kees J. Bot ([e-mail])