
Concrete example: it takes a skill to choose the appropriate `str{pick a letter}cpy` function, and use it without messing up the edge cases.
It may need special include headers or compiler flags on various platforms, which needs more skill and effort to configure the build system and ifdefs appropriately.It can be important and tricky to get right — an amateur could get these wrong, waste time on a project that doesn't build, or even cause a serious security vulnerability!