GETTTYENT(3)

GETTTYENT(3) | Library Functions Manual | GETTTYENT(3)

# NAME

`getttyent`, `getttynam`, `setttyent`, `setttyentpath`, `endttyent` —
get ttys file entry

# LIBRARY

Standard C Library (libc, -lc)

# SYNOPSIS

`#include <ttyent.h>`

struct ttyent *
`getttyent`(void);

struct ttyent *
`getttynam`(const char *name);

int
`setttyent`(void);

int
`setttyentpath`(const char *path);

int
`endttyent`(void);

# 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 */
    	char	*ty_type;	/* terminal type */
    #define	TTY_ON		0x01	/* enable logins */
    #define	TTY_SECURE	0x02	/* allow uid of 0 to login */
    #define	TTY_LOCAL	0x04	/* set 'CLOCAL' on open (dev. specific) */
    #define	TTY_RTSCTS	0x08	/* set 'CRTSCTS' on open (dev. specific) */
    #define	TTY_SOFTCAR	0x10	/* ignore hardware carrier (dev. spec.) */
    #define	TTY_MDMBUF	0x20	/* set 'MDMBUF' on open (dev. specific) */
    #define	TTY_DTRCTS	0x40	/* set 'CDTRCTS' on open (dev. specific) */
    	int	ty_status;	/* flag values */
    	char	*ty_window;	/* command for window manager */
    	char	*ty_comment;	/* comment field */
    	char	*ty_class;	/* category of tty usage */
    };

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_LOCAL`
    If the terminal port's driver supports it, cause the line to be treated as ``local.''
  `TTY_MDMBUF`
    If the terminal port's driver supports it, use DTR/DCD hardware flow control on the line by default.
  `TTY_RTSCTS`
    If the terminal port's driver supports it, use full-duplex RTS/CTS hardware flow control on the line by default.
  `TTY_SOFTCAR`
    If the terminal port's driver supports it, ignore hardware carrier on the line.
ty_window
  The command to execute for a window system associated with the line.
ty_comment
  Any trailing comment field, with any leading hash marks (``#'') or whitespace removed.
ty_class
  A key indexing into a capfile style database (/etc/ttyclasses) of attributes for this class of tty. No attributes are currently defined or used, so there are currently no functions to retrieve them.

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 `setttyentpath`() function is equivalent to `setttyent`() but accepts an additional argument to read the ttys information from an alternate file instead of the default location (defined in `_PATH_TTYS`). 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`() and `setttyentpath`() functions and `endttyent`() return 0 on failure and 1 on success.

# FILES

/etc/ttys

# SEE ALSO

login(1), ttyslot(3), capfile(5), gettytab(5), ttys(5), getty(8), init(8), ttyflags(8)

# HISTORY

The `getttyent`(), `getttynam`(), `setttyent`(), and `endttyent`() functions appeared in 4.3BSD. The `setttyentpath`() function appeared in NetBSD 4.0.

# 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.

February 7, 2014 | NetBSD 9.5