KXErrorHandler

#include <kxerrorhandler.h>

Public Member Functions

 KXErrorHandler (Display *dpy=display())
 
 KXErrorHandler (int(*handler)(Display *, XErrorEvent *), Display *dpy=display())
 
 KXErrorHandler (bool(*handler)(int request, int error_code, unsigned long resource_id), Display *dpy=display())
 
bool error (bool sync) const
 
XErrorEvent errorEvent () const
 

Static Public Member Functions

static Display * display ()
 
static QByteArray errorMessage (const XErrorEvent &e, Display *dpy=display())
 

Detailed Description

This class simplifies handling of X errors.

It shouldn't be necessary to use with Qt classes, as the toolkit should handle X errors itself, so this class will be mainly used with direct Xlib usage, and some lowlevel classes like NETWinInfo.

The usual usage is to create a KXErrorHandler instance right before starting operations that might cause X errors, and checking if there was an error by calling error() after the operations are finished. The handlers may be nested, but must be destroyed in reverse order they were created.

There's no need to do X sync before creating an instance, every instance will handle only errors for request issued after the instance was created. Errors for older requests will be passed to previous error handler. When checking for error by calling error() at the end, it is necessary to sync with X, to catch all errors that were caused by requests issued before the call to error(). This can be done by passing true to error() to cause explicit XSync(), however, if the last X request needed a roundtrip (e.g. XGetWindowAttributes(), XGetGeometry(), etc.), it is not required to do an explicit sync.

Author
Lubos Lunak l.lun[email protected][email protected][email protected]de.or[email protected]g Handler for X errors

Definition at line 59 of file kxerrorhandler.h.

Constructor & Destructor Documentation

KXErrorHandler::KXErrorHandler ( Display *  dpy = display())
explicit

Creates error handler that will set error flag after encountering any X error.

Definition at line 51 of file kxerrorhandler.cpp.

KXErrorHandler::KXErrorHandler ( int(*)(Display *, XErrorEvent *)  handler,
Display *  dpy = display() 
)
explicit

This constructor takes pointer to a function whose prototype matches the one that's used with the XSetErrorHandler() Xlib function.

NOTE: For the error flag to be set, the function must return a non-zero value.

Definition at line 71 of file kxerrorhandler.cpp.

KXErrorHandler::KXErrorHandler ( bool(*)(int request, int error_code, unsigned long resource_id)  handler,
Display *  dpy = display() 
)
explicit

This constructor takes pointer to a function that will get request number, error code number and resource id of the failed request, as provided by XErrorEvent.

If the function returns true, the error flag will be set.

Deprecated:
Use the variant with XErrorEvent.

Definition at line 61 of file kxerrorhandler.cpp.

Member Function Documentation

Display * KXErrorHandler::display ( )
static

This function simply wraps QX11Info::display(), to make sure the public interface doesn't require QtX11Extras.

Definition at line 258 of file kxerrorhandler.cpp.

bool KXErrorHandler::error ( bool  sync) const

This function returns true if the error flag is set (i.e.

no custom handler function was used and there was any error, or the custom handler indicated an error by its return value).

Parameters
syncif true, an explicit XSync() will be done. Not necessary when the last X request required a roundtrip.

Definition at line 97 of file kxerrorhandler.cpp.

XErrorEvent KXErrorHandler::errorEvent ( ) const

This function returns the error event for the first X error that occurred.

The return value is useful only if error() returned true.

Since
4.0.1

Definition at line 105 of file kxerrorhandler.cpp.

QByteArray KXErrorHandler::errorMessage ( const XErrorEvent &  e,
Display *  dpy = display() 
)
static

Returns error message for the given error.

The error message is not translated, as it is meant for debugging.

Since
4.0.1

Definition at line 148 of file kxerrorhandler.cpp.


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