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X11 Error Codes

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Invoking the relevent lower level handlers will be convered below. But at certain scenarios when this Xlib error occur, system calls Xlib Error handler and application crashes. We recommend upgrading to the latest Safari, Google Chrome, or Firefox. BadMatch In a graphics request, the root and depth of the graphics context does not match that of the drawable.

To catch errors and handle them other than by an early exit, two functions are provided: int (*XSetErrorHandler(int (*handler)(Display *, XErrorEvent *)))(); int (*XSetIOErrorHandler(int (*handler)(Display *)))(); Those prototypes (straight from the Liberal use of print statements in your program could help. In rare cases, you may want to hard code the synchronization mode. have the correct depths in your X requests.

X11 Error Codes

Some implementations do not give you this descriptive text, but you may look up the request name, on UNIX systems, in the file /usr/include/X11/Xproto.h, e.g.: % grep 63 /usr/include/X11/Xproto.h #define X_CopyPlane The request_code member is a protocol request of the procedure that failed, as defined in X11/Xproto.h . Not all X implementations are equal, and various X errors are logically survivable.

This should be used only as a last resort because the above methods are simpler and less likely to be forgotten. There is rarely more than one possible BadMatch error for any particular request type, so identifying the problem is usually straight forward. A common idiom for this is to implement an error_trap_push()/error_trap_pop() which just install and de-install your error handler which ignores errors. Xinitthreads You should always call WBErrorClear() to clear out this structure before performing an operation that might result in an XErrorEvent.

If version 3.2 is not supported, an error is returned and it tries to create a context with version 3.1. Xseterrorhandler The answer to this is the fact that there are many reasons why you might want to intercept Xlib's error mechanisms: you might want to attempt a quick application save-state (although Most are available over the World Wide Web at http://www.rahul.net/kenton/bib.html. Note The BadAtom, BadColor, BadCursor, BadDrawable, BadFont, BadGC, BadPixmap, and BadWindow errors are also used when the argument type is extended by a set of fixed alternatives.

Could also be a different Motif behavior or something, or as you say a different X server. –Havoc P Jan 3 '14 at 13:41 add a comment| up vote 0 down Xclosedisplay Does sputtering butter mean that water is present? We recommend upgrading to the latest Safari, Google Chrome, or Firefox. What we can do is install our own handler to try and save application state, analogously to the Xlib XSetErrorHandler routine.

Xseterrorhandler

Worst case, you can end up with UI that thinks it has clickable widgets up, but they're actually deleted, making the application unusable for the end-user. Code to set the Local Error handler :- XSetErrorHandler( LocalErrorHandler ); ..... X11 Error Codes Next: Standard Header Files Christophe Tronche, [email protected] Remlab Home Articles & publications C.V. (PDF) / LinkedIn Contact Projects VLC media player Miredo ndisc6 All Git repositories Web6 (in French) TI-89 & Xgeterrortext You signed out in another tab or window.

This is the reason for the crash of our application. Or, the invalid value could have been generated by a faulty algorithm that computed 0x3. n-dimensional circles! In addition, it is usually linked with pthread-stubs to avoid the POSIX threads overhead in single thread programs. Xsetioerrorhandler

The type parameter indicates the general kind of error; typically, when used by widget authors, it identifies the routine which detects the problem, so for example in Motif it might read Next, we look up the XCopyPlane() function in [Scheifler] to see what error conditions can cause a BadValue error. If the Xlib function is in a subroutine library of which you only have binaries or libraries, you can still use many of the above techniques, but you may have to This is only useful for errors reported by X protocol extensions.

What do you think of having x_error_callback be a no-op by default, unless logging is enabled somehow? Xsync References [Lee91] Kenton Lee, "Behind Curtain X," UNIX Review, vol. 9, no. 6, June, 1991. What do ^$ and ^# mean?

If there has been no error event, the 'pDisplay' member will always be NULL.

And if multiple threads are involved, there is more-or-less no safe way to an error handler at all. For example, again using the UNIX dbx debugger: (dbx) stop in _XError [2] stop in _XError (dbx) run -synchronous [2] stopped at [_XError:2058 ,0x4ea5e4] (dbx) where > 0 _XError ... 1 Unless a specific range is specified for an argument, the full range defined by the argument's type is accepted. If more than one error could be generated for a given request, the server can report any of them.

Whether you like it or not, the client side of the X connection will terminate: your only choice here is to modify the output diagnostic mechanism. WBSupressErrorOutput(); // expect errors, no need for diagnostics WBErrorClear(); while(1) { // perform some operation that does not // normally indicate if an error took place // or needs to be static __inline__ void WBSupressErrorOutput ( void ) static Supress X11 XErrorEvent output to stderr. P.S.

This article discusses simple, but usually sufficient, techniques for understanding X protocol errors and correcting the associated programming problems. Other systems will have similar source level debuggers. By joining our community you will have the ability to post topics, receive our newsletter, use the advanced search, subscribe to threads and access many other special features. Can a level shifting circuit shift voltage the other way around?

octalmage added linux enhancement labels May 8, 2016 octalmage added the ready label May 29, 2016 Sign up for free to join this conversation on GitHub. First, Xlib assumes that any error is fatal by default. To work around this, Xlib provides a synchronous mode where each request is sent immediately to the X server and all errors are reported before new requests are sent. So this needs more diagnostic (with #679) SimonSapin commented Dec 30, 2015 #679 looks good to me.

The advantage of the higher level handler is that it is not necessary to embed messages into the application - these can be externalized so that they can be customized or Reload to refresh your session. The params and num_params arguments specify extra detail associated with the error message; the error or message handler will presumably have to format and concatenate this data when present prior to An Example: redirecting warnings to a popup window #include #include #include static void PopupWarningHandler(String message) { extern Widget application_shell ; /* Session shell ? */ static Widget warning_dialog

If we install an application specific I/O handler, Xlib will terminate after the handler returns in any case. More... The X library considers errors to be of two kinds: fatal, and non-fatal. Error of failed request: BadWindow (invalid Window parameter) Major opcode of failed request: 4 (X_DestroyWindow) I have since learned that these errors can be ignored using a custom X11 error handler

It is necessary to FIRST call WBErrorClear() before any operation that might result in an error that can THEN be checked for using this function. You should use the tables in Appendix A of [Scheifler] to map request types to Xlib functions. (These tables are also available on-line.) In our example, the CopyPlane request is generated The issue we are facing is our application is crashing very frequently in Linux. Each call to the WBSupressErrorOutput() function should be balanced with a call to this function.

To obtain error messages from the error database, use XGetErrorDatabaseText(). To set the error handler, use XSetErrorHandler().