form_fieldtype(3X)      LIBRARY FUNCTIONS      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 vali-
     dates 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 parame-
     ters 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 asso-
     ciates  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:
     E_OK           - The function returned successfully.



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form_fieldtype(3X)      LIBRARY FUNCTIONS      form_fieldtype(3X)



     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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