GETTTYENT(3)

NAME
getttyent, getttynam, setttyent, endttyent - interface to /etc/ttytab

SYNOPSIS
#include <ttyent.h>
struct ttyent *getttyent(void)
struct ttyent *getttynam(const char *name)
int setttyent(void)
void endttyent(void)

DESCRIPTION
The getttyent functions provide an interface to the /etc/ttytab. (See ttytab(5)).

To read one of these files one calls getttyent() several times to read the entries in the table until NULL is returned for end-of-file.

Getttyname() searches the ttytab file for the given terminal device. It is equivalent to a call to setttyent(), several calls to getttyent() to locate the entry, and a final endttyent() to close the file.

Setttyent() opens or rewinds the ttytab database, and endttyent() closes it. Getttyent() opens the database if not already open, but does not close it.

The struct ttyent is defined by <ttyent.h> as follows:

struct ttyent {
	char	*ty_name;	/* Name of the terminal device. */
	char	*ty_type;	/* Terminal type name (termcap(3)). */
	char	**ty_getty;	/* Program to run, normally getty. */
	char	**ty_init;	/* Initialization command, normally stty. */
};

A valid entry has at least two strings, so both ty_name and ty_type are filled in. The optional ty_getty and ty_init may be NULL (field omitted), point to a pointer that is NULL (null lenght field, i.e. ""), or an array of strings terminated by a NULL (field present). For now no useful distinction can be made between a omitted field and an empty field, so treat both cases as an omission.

FILES

/etc/ttytab
    The terminal device database

SEE ALSO
ttyname(3), ttyslot(3), ttytab(5), init(8).

DIAGNOSTICS
Setttyent() has the same return value and error codes as the open(2) call it uses to open the ttytab file. The getxxx() functions return NULL on end of file, entry not found, or error. You can set errno to zero before the call and check it after.

NOTES
Getttyent() and getttynam() return a pointer to static storage that is overwritten in each call.

The MINIX 3 struct ttyent has only the ty_name and ty_type fields in common with the BSD implementation. This does not seem to be a problem, because most third party software that need to know about terminals only look at the ty_name field.

AUTHOR
Kees J. Bot (kjb@cs.vu.nl)