form_driver(3X)                                   form_driver(3X)

NAME
       form_driver - command-processing loop of the form system

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

DESCRIPTION
       Once a form has been posted (displayed), you should funnel
       input events to it through form_driver.  This routine  has
       two  major input cases; either the input is a form naviga-
       tion request or it's a  printable  ASCII  character.   The
       form driver requests are as follows:

       REQ_NEXT_PAGE
            Move to the next page.

       REQ_PREV_PAGE
            Move to the previous page.

       REQ_FIRST_PAGE
            Move to the first page.

       REQ_LAST_PAGE
            Move to the last field.

       REQ_NEXT_FIELD
            Move to the next field.

       REQ_PREV_FIELD
            Move to the previous field.

       REQ_FIRST_FIELD
            Move to the first field.

       REQ_LAST_FIELD
            Move to the last field.

       REQ_SNEXT_FIELD
            Move to the sorted next field.

       REQ_SPREV_FIELD
            Move to the sorted previous field.

       REQ_SFIRST_FIELD
            Move to the sorted first field.

       REQ_SLAST_FIELD
            Move to the sorted last field.

       REQ_LEFT_FIELD
            Move left to a field.

       REQ_RIGHT_FIELD
            Move right to a field.

       REQ_UP_FIELD
            Move up to a field.

       REQ_DOWN_FIELD
            Move down to a field.

       REQ_NEXT_CHAR
            Move to the next char.

       REQ_PREV_CHAR
            Move to the previous char.

       REQ_NEXT_LINE
            Move to the next line.

       REQ_PREV_LINE
            Move to the previous line.

       REQ_NEXT_WORD
            Move to the next word.

       REQ_PREV_WORD
            Move to the previous word.

       REQ_BEG_FIELD
            Move to the beginning of the field.

       REQ_END_FIELD
            Move to the end of the field.

       REQ_BEG_LINE
            Move to the beginning of the line.

       REQ_END_LINE
            Move to the end of the line.

       REQ_LEFT_CHAR
            Move left in the field.

       REQ_RIGHT_CHAR
            Move right in the field.

       REQ_UP_CHAR
            Move up in the field.

       REQ_DOWN_CHAR
            Move down in the field.

       REQ_NEW_LINE
            Insert or overlay a new line.

       REQ_INS_CHAR
            Insert a blank at the cursor.

       REQ_INS_LINE
            Insert a blank line at the cursor.

       REQ_DEL_CHAR
            Delete character at the cursor.

       REQ_DEL_PREV
            Delete character before the cursor.

       REQ_DEL_LINE
            Delete line at the cursor.

       REQ_DEL_WORD
            Delete blank-delimited word at the cursor.

       REQ_CLR_EOL
            Clear to end of line from cursor.

       REQ_CLR_EOF
            Clear to end of field from cursor.

       REQ_CLR_FIELD
            Clear the entire field.

       REQ_OVL_MODE
            Enter overlay mode.

       REQ_INS_MODE
            Enter insert mode.

       REQ_SCR_FLINE
            Scroll the field forward a line.

       REQ_SCR_BLINE
            Scroll the field backward a line.

       REQ_SCR_FPAGE
            Scroll the field forward a page.

       REQ_SCR_BPAGE
            Scroll the field backward a page.

       REQ_SCR_FHPAGE
            Scroll the field forward half a page.

       REQ_SCR_BHPAGE
            Scroll the field backward half a page.

       REQ_SCR_FCHAR
            Scroll the field forward a character.

       REQ_SCR_BCHAR
            Scroll the field backward a character.

       REQ_SCR_HFLINE
            Horizontal scroll the field forward 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_HBHALF
            Horizontal scroll the field backward half a line.

       REQ_VALIDATION
            Validate field.

       REQ_NEXT_CHOICE
            Display next field choice.

       REQ_PREV_CHOICE
            Display previous field choice.

       If the second argument is a printable ASCII 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.

       If the second argument is neither printable ASCII nor  one
       of  the above pre-defined form requests, the drive assumes
       it  is  an  application-specific   command   and   returns
       E_UNKNOWN_COMMAND.  Application-defined commands should be
       defined relative to  MAX_COMMAND,  the  maximum  value  of
       these pre-defined requests.

RETURN VALUE
       form_driver return one of the following error codes:

       E_OK The routine succeeded.

       E_SYSTEM_ERROR
            System error occurred (see errno).

       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_UNKNOWN_COMMAND
            The form driver code saw an unknown request code.

       E_INVALID_FIELD
            Contents of field is invalid.

       E_REQUEST_DENIED
            The form driver could not process the request.

SEE ALSO
       curses(3X), form(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.

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