I'm currently doing some tests using Cairo to replace some existing GDI/GDI+ code in Visual C++ 2010 and it seems to be working fine, but I'm getting an error message each time I close down my application :
"First-chance exception at 0x68e629dc in CairoTest.exe: 0xC0000005: Access violation reading location 0xabababa7"
This error only happens if I've called cairo_paint(cr) while the application is running - if I comment this line out, it disappears. The only Cairo code in my application so far is :
CChildView::CChildView()
{
testsurface = cairo_image_surface_create_from_png("BlackShinyBackground.png");
}
CChildView::~CChildView()
{
cairo_surface_destroy(testsurface);
}
void CChildView::OnPaint()
{
CPaintDC dc(this);
cairo_surface_t *surface = cairo_win32_surface_create(dc.m_hDC);
cairo_t *cr = cairo_create (surface);
cairo_set_source_surface(cr, testsurface, 0, 0);
cairo_paint(cr);
cairo_destroy (cr);
cairo_surface_destroy (surface);
}
Can anybody point me in the 开发者_运维知识库direction of what I'm doing wrong?
Like I said, the code appearsto be working fine, but I don't like just ploughing on regardless when I can see errors.
A first chance exception doesn't necessarily mean much -- they're a routine part of Windows' memory management. Basically, any time you access something that's in virtual memory (e.g., on the paging file) a first chance exception is created. The OS handles it by paging in the required data into physical memory, then your code can continue executing.
If/when you see a second-chance exception, it means the OS didn't handle the exception, so unless you have a handler for it in your code, chances are pretty good that is signals a real problem.
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