driver(3form)

NAME

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 three major input cases:

- The input is a form navigation request. Navigation request codes

are constants defined in <form.h>, which are distinct from the keyand character codes returned by wgetch.

- The input is a printable character. Printable characters (which

must be positive, less than 256) are checked according to the program's locale settings.

- The input is the KEY_MOUSE special key associated with an mouse

event.

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 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 decoration 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:

- the form cursor is positioned to that field.

- 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 purpose of this return value to signal that an application specific command should be executed.

- 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 predefined form requests, the driver 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 returns one of the following error codes:

E_OK The routine succeeded.

E_BAD_ARGUMENT

Routine detected an incorrect or out-of-range argument.

E_BAD_STATE

Routine was called from an initialization or termination 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

ncurses(3NCURSES), form(3FORM), wgetch(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.

driver(3FORM)