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 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)