Get a pointer to the current function in C (gcc)?

Asked 2010-01-28T13:41:08.807

is there a magic variable in gcc holding a pointer to the current function ?

I would like to have a kind of table containing for each function pointer a set of information.

I know there's a __func__ variable containing the name of the current function as a string but not as a function pointer.

This is not to call the function then but just to be used as an index.

EDIT Basically what i would like to do is being able to run nested functions just before the execution of the current function (and also capturing the return to perform some things.) Basically, this is like __cyg_profile_func_enter and __cyg_profile_func_exit (the instrumentation functions)... But the problem is that these instrumentation functions are global and not function-dedicated.

EDIT In the linux kernel, you can use unsigned long kallsyms_lookup_name(const char *name) from include/linux/kallsyms.h ... Note that the CONFIG_KALLSYMS option must be activated.

c gcc function-pointers

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2 Answers

If you want to do this in a 'generic' way, then you should use the facilities you already mention (__cyg_profile_func*) since that is what they are designed for. Anything else will have to be as ad hoc as your profile.

Honestly, doing things the generic way (with a filter) is probably less error prone than any new method that you will insert on-the-fly.

answered 2010-01-28T15:00:21.530

You can capture this information with setjmp(). Since it saves enough information to return to your current function, it must include that information in the provided jmp_buf.

This structure is highly nonportable, but you mention GCC explicitly so that's probably not a blocking issue. See this GCC/x86 example to get an idea how it roughly works.

answered 2010-01-28T15:43:51.723

Get a pointer to the current function in C (gcc)?

2 Answers

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