source: trunk/ncurses/man/menu_driver.3x@ 2996

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.\" $Id: menu_driver.3x,v 1.11 2003/05/10 20:22:01 tom Exp $
.TH menu_driver 3X ""
.SH NAME
\fBmenu_driver\fR - command-processing loop of the menu system
.SH SYNOPSIS
\fB#include <menu.h>\fR
.br
int menu_driver(MENU *menu, int c);
.br
.SH DESCRIPTION
Once a menu has been posted (displayed), you should funnel input events to it
through \fBmenu_driver\fR.  This routine has three major input cases; either
the input is a menu navigation request, it's a printable ASCII character or it
is the KEY_MOUSE special key associated with an mouse event.
The menu driver requests are as follows:
.TP 5
REQ_LEFT_ITEM
Move left to an item.
.TP 5
REQ_RIGHT_ITEM
Move right to an item.
.TP 5
REQ_UP_ITEM
Move up to an item.
.TP 5
REQ_DOWN_ITEM
Move down to an item.
.TP 5
REQ_SCR_ULINE
Scroll up a line.
.TP 5
REQ_SCR_DLINE
Scroll down a line.
.TP 5
REQ_SCR_DPAGE
Scroll down a page.
.TP 5
REQ_SCR_UPAGE
Scroll up a page.
.TP 5
REQ_FIRST_ITEM
Move to the first item.
.TP 5
REQ_LAST_ITEM
Move to the last item.
.TP 5
REQ_NEXT_ITEM
Move to the next item.
.TP 5
REQ_PREV_ITEM
Move to the previous item.
.TP 5
REQ_TOGGLE_ITEM
Select/deselect an item.
.TP 5
REQ_CLEAR_PATTERN
Clear the menu pattern buffer.
.TP 5
REQ_BACK_PATTERN
Delete the previous character from the pattern buffer.
.TP 5
REQ_NEXT_MATCH
Move to the next item matching the pattern match.
.TP 5
REQ_PREV_MATCH
Move to the previous item matching the pattern match.
.PP
If the second argument is a printable ASCII character, the code appends
it to the pattern buffer and attempts to move to the next item matching
the new pattern.  If there is no such match, \fBmenu_driver\fR returns
\fBE_NO_MATCH\fR and deletes the appended character from the buffer.
.PP
If the second argument is one of the above pre-defined requests, the
corresponding action is performed.
.PP
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 menu display
area or the decoration window) are handled. If you click above the
display region of the menu, a REQ_SCR_ULINE is generated, if you
doubleclick a REQ_SCR_UPAGE is generated and if you tripleclick a
REQ_FIRST_ITEM is generated. If you click below the display region of
the menu, a REQ_SCR_DLINE is generated, if you doubleclick a REQ_SCR_DPAGE
is generated and if you tripleclick a REQ_LAST_ITEM is generated. If you
click at an item inside the display area of the menu, the menu cursor
is positioned to that item. If you double-click at an item a REQ_TOGGLE_ITEM
is generated and \fBE_UNKNOWN_COMMAND\fR is returned. This return value makes
sense, because a double click usually means that an item-specific action should
be returned. It's 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, \fBmenu_driver\fR returns the result of this request.
If you clicked outside the user window or the mouse event couldn't be translated
into a menu request an \fBE_REQUEST_DENIED\fR is returned.
.PP
If the second argument is neither printable ASCII nor one of the above
pre-defined menu requests or KEY_MOUSE, the drive assumes it is an application-specific
command and returns \fBE_UNKNOWN_COMMAND\fR.  Application-defined commands
should be defined relative to \fBMAX_COMMAND\fR, the maximum value of these
pre-defined requests.
.SH RETURN VALUE
\fBmenu_driver\fR return one of the following error codes:
.TP 5
\fBE_OK\fR
The routine succeeded.
.TP 5
\fBE_SYSTEM_ERROR\fR
System error occurred (see \fBerrno\fR).
.TP 5
\fBE_BAD_ARGUMENT\fR
Routine detected an incorrect or out-of-range argument.
.TP 5
\fBE_BAD_STATE\fR
Routine was called from an initialization or termination function.
.TP 5
\fBE_NOT_POSTED\fR
The menu has not been posted.
.TP 5
\fBE_UNKNOWN_COMMAND\fR
The menu driver code saw an unknown request code.
.TP 5
\fBE_NO_MATCH\fR
Character failed to match.
.TP 5
\fBE_REQUEST_DENIED\fR
The menu driver could not process the request.
.SH SEE ALSO
\fBcurses\fR(3X), \fBmenu\fR(3X).
.SH NOTES
The header file \fB<menu.h>\fR automatically includes the header files
\fB<curses.h>\fR.
.SH PORTABILITY
These routines emulate the System V menu library.  They were not supported on
Version 7 or BSD versions. The support for mouse events is ncurses specific.
.SH AUTHORS
Juergen Pfeifer.  Manual pages and adaptation for new curses by Eric
S. Raymond.
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