> qsort is a function inside of libc.so. It's already been compiled.
Unfortunately, this is also why it is so damn slow. Try comparing C++ std::sort with C qsort, the performance gap is HUGE. The reason is that the "function pointer" std::sort gets inlined but qsort will actually invoke a function call via function pointer.
If you'd move qsort to a header file as an inline function, the performance problem would go away.
This is one thing I don't understand about HN sometimes. I always get replies that seen to angrily "disagree". But I've already made your point in my parenthetical remark.
There are of course other times where the function pointer overhead doesn't matter as much and the modularity of not having things as templates is desirable. Sorting is just a bad example.
Unfortunately, this is also why it is so damn slow. Try comparing C++ std::sort with C qsort, the performance gap is HUGE. The reason is that the "function pointer" std::sort gets inlined but qsort will actually invoke a function call via function pointer.
If you'd move qsort to a header file as an inline function, the performance problem would go away.