form_fieldtype(3X)                                       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)                                       form_fieldtype(3X)


         EOK           - The function returned successfully.
         ESYSTEMERROR - System error.
         EBADARGUMENT - An argument is incorrect.
         ECONNECTED    - 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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