getttyent (3)

#include <ttyent.h>

struct ttyent *getttyent(void);

struct ttyent *getttynam(const char *name);

int setttyent(void);

int endttyent(void);

These functions provide an interface to the file _PATH_TTYS (e.g., /etc/ttys).

The function setttyent() opens the file or rewinds it if already open.

The function endttyent() closes the file.

The function getttynam() searches for a given terminal name in the file. It returns a pointer to a ttyent structure (description below).

The function getttyent() opens the file _PATH_TTYS (if necessary) and returns the first entry. If the file is already open, the next entry. The ttyent structure has the form:

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 */
};

ty_status can be:

#define TTY_ON     0x01  /* enable logins (start ty_getty program) */
#define TTY_SECURE 0x02  /* allow UID 0 to login */

Multithreading (see pthreads(7))

The getttyent() function returns a pointer to a static variable, so it is not thread-safe.

The setttyent() and endttyent() functions use a static variable, so they are not thread-safe.

The getttynam() function calls thread-unsafe function getttyent() so it is not thread-safe.

Not in POSIX.1-2001. Present on the BSDs, and perhaps other systems.

Under Linux, the file /etc/ttys, and the functions described above, are not used.

ttyname(3), ttyslot(3)

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