https://invisible-island.net/xterm/xtoolkit/
XtError, XtSetErrorHandler, XtSetWarningHandler, XtWarning - low-level error handlers
#include <X11/Intrinsic.h> _X_NORETURN void XtError(const char *message); void XtSetErrorHandler(_X_NORETURN XtErrorHandler handler); void XtSetWarningHandler(XtErrorHandler handler); void XtWarning(const char *message);
message Specifies the nonfatal error message that is to be reported. handler Specifies the new fatal error procedure, which should not re- turn, or the nonfatal error procedure, which usually returns. message Specifies the message that is to be reported.
The XtError function has been superseded by XtAppError. The XtSetErrorHandler function has been superseded by XtAppSetErrorHan- dler. The XtSetWarningHandler function has been superseded by XtAppSetWarn- ingHandler. The XtWarning function has been superseded by XtAppWarning.
XtAppError(3) X Toolkit Intrinsics - C Language Interface Xlib - C Language X Interface X Version 11 libXt 1.3.1 XtError(3)