LOL that's why I love C!

The function pointer cast for strcmp because qsort expects a compare function with two const void * pointers instead of two const char * pointers, that's just beautiful.

Not to mention the hack to abuse strcmp on a struct - which just works because the first struct member is a string and the rest just gets swapped with memcpy as opaque data.

I guess that wouldn't pass a code review at work. :-)

Sometimes my hatred for code is so.. overwhelming that I think I need a sabbatical or should even stop altogether.

Let's face it. All code sucks. Just on different levels.
Want to go all bare metal? Love low level bit fiddling. Well, have fun searching for concurrency, memory corruption bugs. Still feel confident? Get ulcers from large C/C++ code base already in production, where something in the shared memory, function pointer magic is not totally right?
So you strive for more clean abstractions, fancy the high level stuff? Well, can you make sense of gcc's template error messages, are you ready for the monad, leaving behind the mundane everyday programmers, who still wonders about the scope of x and xs?

Wherever you go. Isn't it a stinking shit pile of entropy, arbitrary human made conventions? You're just getting more familiar with them, so you don't question them, they become your second skin, you become proficient - congrats you're a member of the 1337.

Built the most generic file importer.
So a customer had his SAP system giving us some 5 million barcodes in a csv which we needed to parse. But as there could be different file types and I thought the handling would always include the same steps I made them configurable through function pointers. - Did not want to make it as spooky as the rest of the code base where the function pointers were buried deep in some shared memory configs, which might even change at run time, but rather I statically used the member functions of my class. Just to poke fun on the ugly C++ syntax of member function pointers. I still shudder at the thought some poor soul now has to maintain that code.
(For the actual parsing I actually used a one liner in awk which was churning through the records in one minute which was faster than the SAP guys seemed to be accustomed to.)

Why the pointer of member function so special.

trying make a non-template class that like std::function but simpler:
1. wrap static function pointer.
2. wrap class member function pointer and the class object pointer.
3. WITHOUT ALLOCATE MEMORY.

I can't store member function pointer because the size is undefined?!

Just realized a member function pointer can be a template parameter as non-type, gonna try to use it do no dynamic memory allocation trick with std::function.