For example, i am trying to run GWIN/slider example. Here is the code from main.c #include "gfx.h" static GListener gl; static GHandle ghSlider1, ghSlider2, ghConsole; static void createWidgets(void) { GWidgetInit wi; // Apply some default values for GWIN gwinWidgetClearInit(&wi); wi.g.show = TRUE; // create Slider1 wi.g.y = 10; wi.g.x = 10; wi.g.width = gdispGetWidth()-20; wi.g.height = 20; wi.text = "S1"; ghSlider1 = gwinSliderCreate(0, &wi); // create Slider2 wi.g.y = 40; wi.g.x = 10; wi.g.width = 20; wi.g.height = gdispGetHeight() - 50; wi.text = "S2"; ghSlider2 = gwinSliderCreate(0, &wi); // Set slider 2 to return extended events gwinSliderSendExtendedEvents(ghSlider2, TRUE); // Some options to try //gwinSliderSetRange(ghSlider1, 0, 70000); //gwinSliderSetRange(ghSlider2, -4, 4); //gwinSliderSetRange(ghSlider1, 4, -4); // Console to display slider events wi.g.y = 40; wi.g.x = 40; wi.g.width = gdispGetWidth()-50; wi.g.height = gdispGetHeight()-50; ghConsole = gwinConsoleCreate(0, &wi.g); } void cyg_user_start(void){ GEventGWinSlider * pe; const char * sAction; // Initialize the display gfxInit(); // Set the widget defaults gwinSetDefaultFont(gdispOpenFont("UI2")); gwinSetDefaultStyle(&WhiteWidgetStyle, FALSE); gdispClear(White); // create the widget createWidgets(); gwinSetColor(ghConsole, Green); gwinSetBgColor(ghConsole, White); gwinClear(ghConsole); // We want to listen for widget events geventListenerInit(&gl); gwinAttachListener(&gl); while(1) { // Get an Event (assume it is a slider event) pe = (GEventGWinSlider *)geventEventWait(&gl, TIME_INFINITE); switch(pe->type) { case GEVENT_GWIN_SLIDER: switch(pe->action) { case GSLIDER_EVENT_SET: sAction = "SET"; break; case GSLIDER_EVENT_CANCEL: sAction = "CANCEL"; break; case GSLIDER_EVENT_MOVE: sAction = "MOVE"; break; case GSLIDER_EVENT_START: sAction = "START"; break; default: sAction = "????"; break; } gwinPrintf(ghConsole, "Slider %s = %d %s\n", gwinGetText(pe->gwin), pe->position, sAction); break; default: // Oops - not a slider event. break; } } } The program can't reach "switch(pe->type)" line. When i suspend debug session, i see, that an exception occured. For example, the program reach "cyg_posix_exception_handler" with exception number 3. I also noticed that exception occured on line 109 in file packages/kernel/current/src/sync/cnt_sem.cxx // Allow other threads to run Cyg_Scheduler::reschedule(); Maybe i should run ugfx from thread?