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form_driver 3x

form_driver(3x)                                         form_driver(3x)




NAME

       form_driver,  form_driver_w  -  command-processing loop of
       the form system


SYNOPSIS

       #include <form.h>
       int form_driver(FORM *form, int c);
       int form_driver_w(FORM *form, int c, wchar_t wch);


DESCRIPTION


form_driver

       Once a form has been posted (displayed), you should funnel
       input  events to it through form_driver.  This routine has
       three major input cases:

       o   The input is a form  navigation  request.   Navigation
           request codes are constants defined in <form.h>, which
           are  distinct  from  the  key-  and  character   codes
           returned by wgetch(3x).

       o   The input is a printable character.  Printable charac-
           ters (which must  be  positive,  less  than  256)  are
           checked according to the program's locale settings.

       o   The input is the KEY_MOUSE special key associated with
           an mouse event.


form_driver_w

       This extension simplifies the use  of  the  forms  library
       using  wide characters.  The input is either a key code (a
       request) or a wide character returned by get_wch(3x).  The
       type  must  be  passed  as  well, to enable the library to
       determine whether the parameter is a wide character  or  a
       request.


Form-driver requests

       The form driver requests are as follows:

       Name               Description
       -------------------------------------------------------------------------
       REQ_BEG_FIELD      Move to the beginning of the field.
       REQ_BEG_LINE       Move to the beginning of the line.
       REQ_CLR_EOF        Clear to end of field from cursor.
       REQ_CLR_EOL        Clear to end of line from cursor.
       REQ_CLR_FIELD      Clear the entire field.
       REQ_DEL_CHAR       Delete character at the cursor.
       REQ_DEL_LINE       Delete line at the cursor.
       REQ_DEL_PREV       Delete character before the cursor.
       REQ_DEL_WORD       Delete blank-delimited word at the cursor.
       REQ_DOWN_CHAR      Move down in the field.
       REQ_DOWN_FIELD     Move down to a field.
       REQ_END_FIELD      Move to the end of the field.
       REQ_END_LINE       Move to the end of the line.
       REQ_FIRST_FIELD    Move to the first field.
       REQ_FIRST_PAGE     Move to the first page.
       REQ_INS_CHAR       Insert a blank at the cursor.
       REQ_INS_LINE       Insert a blank line at the cursor.
       REQ_INS_MODE       Enter insert mode.
       REQ_LAST_FIELD     Move to the last field.
       REQ_LAST_PAGE      Move to the last field.
       REQ_LEFT_CHAR      Move left in the field.

       REQ_LEFT_FIELD     Move left to a field.
       REQ_NEW_LINE       Insert or overlay a new line.
       REQ_NEXT_CHAR      Move to the next char.
       REQ_NEXT_CHOICE    Display next field choice.
       REQ_NEXT_FIELD     Move to the next field.
       REQ_NEXT_LINE      Move to the next line.
       REQ_NEXT_PAGE      Move to the next page.
       REQ_NEXT_PAGE      Move to the next page.
       REQ_NEXT_WORD      Move to the next word.
       REQ_OVL_MODE       Enter overlay mode.
       REQ_PREV_CHAR      Move to the previous char.
       REQ_PREV_CHOICE    Display previous field choice.
       REQ_PREV_FIELD     Move to the previous field.
       REQ_PREV_LINE      Move to the previous line.
       REQ_PREV_PAGE      Move to the previous page.
       REQ_PREV_WORD      Move to the previous word.
       REQ_RIGHT_CHAR     Move right in the field.
       REQ_RIGHT_FIELD    Move right to a field.
       REQ_SCR_BCHAR      Scroll the field backward a character.
       REQ_SCR_BHPAGE     Scroll the field backward half a page.
       REQ_SCR_BLINE      Scroll the field backward a line.
       REQ_SCR_BPAGE      Scroll the field backward a page.
       REQ_SCR_FCHAR      Scroll the field forward a character.
       REQ_SCR_FHPAGE     Scroll the field forward half a page.
       REQ_SCR_FLINE      Scroll the field forward a line.
       REQ_SCR_FPAGE      Scroll the field forward a page.
       REQ_SCR_HBHALF     Horizontal scroll the field backward half a line.
       REQ_SCR_HBLINE     Horizontal scroll the field backward a line.
       REQ_SCR_HFHALF     Horizontal scroll the field forward half a line.
       REQ_SCR_HFLINE     Horizontal scroll the field forward a line.
       REQ_SFIRST_FIELD   Move to the sorted first field.
       REQ_SLAST_FIELD    Move to the sorted last field.
       REQ_SNEXT_FIELD    Move to the sorted next field.
       REQ_SPREV_FIELD    Move to the sorted previous field.
       REQ_UP_CHAR        Move up in the field.
       REQ_UP_FIELD       Move up to a field.
       REQ_VALIDATION     Validate field.

       If  the  second  argument  is  a  printable character, the
       driver places it in the current position  in  the  current
       field.   If  it is one of the forms requests listed above,
       that request is executed.


Mouse handling

       If the second argument is the KEY_MOUSE special  key,  the
       associated mouse event is translated into one of the above
       pre-defined requests.  Currently only clicks in  the  user
       window  (e.g., inside the form display area or the decora-
       tion window) are handled.

       If you click above the display region of the form:

          a REQ_PREV_FIELD is generated for a single click,

          a REQ_PREV_PAGE is generated for a double-click and

          a REQ_FIRST_FIELD is generated for a triple-click.

       If you click below the display region of the form:

          a REQ_NEXT_FIELD is generated for a single click,

          a REQ_NEXT_PAGE is generated for a double-click and

          a REQ_LAST_FIELD is generated for a triple-click.

       If you click at an field inside the display  area  of  the
       form:

          o   the form cursor is positioned to that field.

          o   If  you  double-click  a  field, the form cursor is
              positioned to that field and  E_UNKNOWN_COMMAND  is
              returned.  This return value makes sense, because a
              double click usually means that  an  field-specific
              action  should be returned.  It is exactly the pur-
              pose of this return value to signal that an  appli-
              cation specific command should be executed.

          o   If   a   translation   into  a  request  was  done,
              form_driver returns the result of this request.

       If you clicked outside the user window or the mouse  event
       could   not   be   translated   into  a  form  request  an
       E_REQUEST_DENIED is returned.


Application-defined commands

       If the second argument is neither printable nor one of the
       above  pre-defined form requests, the driver assumes it is
       an application-specific command and returns E_UNKNOWN_COM-
       MAND.  Application-defined commands should be defined rel-
       ative to MAX_COMMAND, the  maximum  value  of  these  pre-
       defined requests.


RETURN VALUE

       form_driver returns one of the following error codes:

       E_OK The routine succeeded.

       E_BAD_ARGUMENT
            Routine  detected  an incorrect or out-of-range argu-
            ment.

       E_BAD_STATE
            Routine was called from an initialization or termina-
            tion function.

       E_NOT_POSTED
            The form has not been posted.

       E_INVALID_FIELD
            Contents of field is invalid.

       E_REQUEST_DENIED
            The form driver could not process the request.

       E_SYSTEM_ERROR
            System error occurred (see errno).

       E_UNKNOWN_COMMAND
            The form driver code saw an unknown request code.


SEE ALSO

       curses(3x), form(3x), form_variables(3x), curs_getch(3x).


NOTES

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


PORTABILITY

       These routines emulate the System V forms  library.   They
       were not supported on Version 7 or BSD versions.


AUTHORS

       Juergen  Pfeifer.   Manual  pages  and  adaptation for new
       curses by Eric S. Raymond.



                                                        form_driver(3x)