how to get the pc register for any thread on Linux?

My debug thread will monitor the memory开发者_开发技巧 usage. When it finds the inconsistency situation it will generate a coredump.

As I found, the coredump is not very accurate (looks a bit later than the moment the problem happened, because I need to do some cleanup in the debug thread before abort()).

I want to record the exact %pc register of the thread val at that time, how can I do that?

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One way to get a 'recent' %pc --program counter-- (also know as %ip instruction pointer) is to save the state of your process with makecontext

void makecontext(ucontext_t *ucp, void (*func)(), int argc, ...);

and read the right value in the buffer: REG_EIP as defined in sys/ucontext.h

context.uc_mcontext.gregs[REG_EIP];

Please note that the data structure is obviously machine-dependent, and for instance, if you were using a SPARC, the %ip would have been stored in REG_RIP

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as far as I know, there is no way to read this value for all the threads, you'll have to read the %pc on each of them, and gather manually your data.