Is there a way to set a breakpoint on the first instruction of a program, in visualstudio? No I don't mean on main - I mean on the very first thing, i.e. global constructor code. Also, I tried to set a breakpoint on mainCRTStartup and... it doesn't trigger? I suspect there is some write protection so that the debugger can't patch the int instruction? Is this a new thing?
@c0de517e I was able to step out of my main and find mainCRTStartup and friends. Breakpoints there worked, at least in debug build. Static constructors are run from mainCRTStartup I guess but there are some hidden layers.
@c0de517e I want to remember that vs at some point had an option to launch a program with debugger attached and breaking it right away, but it might be a dream.
@breakin win11/vs22 enterprise, every time I try to put a break on mainCRTStartup it gets disabled and does not trigger - but I side-stepped the issue by creating a static instance in a translation unit marked with pragma init_seg(compiler)
@rvkennedy not really, it gets to the userland winmain, not the library and definitely not the first code instruction (all of that is way after all global init)
@c0de517e Yes you're quite right. Interestingly, breakpoints can be set e.g. in main.cpp on any line that produces runtime code, such as a declaration that launches a constructor. But how to stop at the first code.. Looking up my callstack (and this will be compiler- and runtime-dependent) I see a fn called _initterm() which loops through initializer functions calling them in turn. This seems to be where the globals are created. You can break in _initterm, I don't know if that's the first.
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