通常，仅自托管的系统编译器无法提供完整的Standard C环境，包括运行时库.通常，底层系统提供大多数(如果不是全部)库(和标头)，而编译器仅进行编译.

Typically a self-hosted system compiler alone does not provide the full Standard C environment including runtime libraries. Typically the underlying system provides most, if not all, of the libraries (and headers), while the compiler just compiles.

因此，如果需要给定系统上未提供的某些特定功能，则必须自己编写它们，或从与目标系统兼容的某些可移植库中获取它们.

So, if you need some specific functions that are not provided on a given system then you will have to write them yourself, or source them from some portable library that is compatible with your target system.

在这种特殊情况下，您可能还会发现系统的 libc 本身未提供 quick_exit()本身，因此编写这两个函数应该足够容易靠你自己.

In this particular case you will also probably find that quick_exit() itself is not provided by the system's libc, and so it should be easy enough to write both functions on your own.