form_fieldtype(3X)               UNIX System V               form_fieldtype(3X)


NAME
      formfieldtype:  newfieldtype, freefieldtype, setfieldtypearg,
      setfieldtypechoice, linkfieldtype - forms fieldtype routines

SYNOPSIS
      #include <form.h>

      FIELDTYPE *newfieldtype(int (* fieldcheck)(FIELD *, char *),
            int (* charcheck)(int, char *));
      int freefieldtype(FIELDTYPE *fieldtype);
      int setfieldtypearg(FIELDTYPE *fieldtype,
            char *(* makarg)(valist *),
            char *(* copyarg)(char *), void (* freearg)(char *));
      int setfieldtypechoice(FIELDTYPE *fieldtype,
            int (* nextchoice)(FIELD *, char *),
            int (* prevchoice)(FIELD *, char *));
      FIELDTYPE *linkfieldtype(FIELDTYPE *type1, FIELDTYPE *type2);

DESCRIPTION
      newfieldtype creates a new field type.  The application programmer must
      write the function field_check, which validates the field value, and the
      function char_check, which validates each character.  freefieldtype
      frees the space allocated for the field type.

      By associating function pointers with a field type, setfieldtypearg
      connects to the field type additional arguments necessary for a
      setfieldtype call.  Function mak_arg allocates a structure for the
      field specific parameters to setfieldtype and returns a pointer to the
      saved data.  Function copy_arg duplicates the structure created by
      make_arg.  Function free_arg frees any storage allocated by make_arg or
      copy_arg.

      The formdriver requests REQNEXTCHOICE and REQPREVCHOICE let the user
      request the next or previous value of a field type comprising an ordered
      set of values.  setfieldtypechoice allows the application programmer to
      implement these requests for the given field type.  It associates with
      the given field type those application-defined functions that return
      pointers to the next or previous choice for the field.

      linkfieldtype returns a pointer to the field type built from the two
      given types.  The constituent types may be any application-defined or
      pre-defined types.

RETURN VALUE
      Routines that return pointers always return NULL on error.  Routines that
      return an integer return one of the following:








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form_fieldtype(3X)               UNIX System V               form_fieldtype(3X)


      E_OK           - The function returned successfully.
      E_SYSTEM_ERROR - System error.
      E_BAD_ARGUMENT - An argument is incorrect.
      E_CONNECTED    - Type is connected to one or more fields.

NOTES
      The header file <form.h> automatically includes the header files <eti.h>
      and <curses.h>.

SEE ALSO
      curses(3X), forms(3X)











































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