GETTTYENT(3)

NAME
getttyent, getttynam, setttyent, endttyent, isdialuptty, isnettty - ttys(5) file routines

LIBRARY
libc

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

DESCRIPTION
The getttyent(), and getttynam() functions each return a pointer to an object, with the following structure, containing the broken-out fields of a line from the tty description file.

    struct ttyent {
    	char	*ty_name;	/* terminal device name */
    	char	*ty_getty;	/* command to execute, usually getty */
    	char	*ty_type;	/* terminal type for termcap */
    	int	ty_status;	/* status flags */
    	char	*ty_window;	/* command to start up window manager */
    	char	*ty_comment;	/* comment field */
    	char	*ty_group;	/* tty group name */
    };

The fields are as follows:

ty_name
    The name of the character-special file.

ty_getty
    The name of the command invoked by init(8) to initialize tty line characteristics.

ty_type
    The name of the default terminal type connected to this tty line.

ty_status
    A mask of bit fields which indicate various actions allowed on this tty line. The possible flags are as follows:

    TTY_ON
        Enables logins (i.e., init(8) will start the command referenced by ty_getty on this entry).

    TTY_SECURE
        Allow users with a uid of 0 to login on this terminal.

    TTY_DIALUP
        Identifies a tty as a dialin line. If this flag is set, then isdialuptty() will return a non-zero value.

    TTY_NETWORK
        Identifies a tty used for network connections. If this flag is set, then isnettty() will return a non-zero value.

    TTY_IFCONSOLE
        Only enables a tty if it's the console.

    TTY_IFEXISTS
        Only enables a tty if it exists.

ty_window
    The command to execute for a window system associated with the line.

ty_group
    A group name to which the tty belongs. If no group is specified in the ttys description file, then the tty is placed in an anonymous group called “none”.

ty_comment
    Any trailing comment field, with any leading hash marks (#) or whitespace removed.

If any of the fields pointing to character strings are unspecified, they are returned as null pointers. The field ty_status will be zero if no flag values are specified.

See ttys(5) for a more complete discussion of the meaning and usage of the fields.

The getttyent() function reads the next line from the ttys file, opening the file if necessary. The setttyent() function rewinds the file if open, or opens the file if it is unopened. The endttyent() function closes any open files.

The getttynam() function searches from the beginning of the file until a matching name is found (or until EOF is encountered).

RETURN VALUES
The routines getttyent() and getttynam() return a null pointer on EOF or error. The setttyent() function and endttyent() return 0 on failure and 1 on success.

The routines isdialuptty() and isnettty() return non-zero if the dialup or network flag is set for the tty entry relating to the tty named by the argument, and zero otherwise.

FILES
/etc/ttys

SEE ALSO
login(1), gettytab(5), termcap(5), ttys(5), getty(8), init(8)

HISTORY
The getttyent(), getttynam(), setttyent(), and endttyent() functions appeared in 4.3BSD.

BUGS
These functions use static data storage; if the data is needed for future use, it should be copied before any subsequent calls overwrite it.