在什么情况下 alloca() 有用?

In which cases is alloca() useful?(在什么情况下 alloca() 有用?)

问题描述

当您总是可以在堆栈上分配一个足够大以适应所有用途的固定大小缓冲区时，为什么还要使用 alloca()?这不是一个反问句……

Why would you ever want to use alloca() when you could always allocate a fixed size buffer on the stack large enough to fit all uses? This is not a rhetorical question...

推荐答案

如果缓冲区的大小在运行时变化，或者您只是有时需要它，这可能会很有用:这将比固定使用更少的堆栈空间 -每次调用中的大小缓冲区.特别是如果函数位于堆栈的高位或递归.

It could be useful if the size of the buffer varies at runtime, or if you only sometimes need it: this would use less stack space overall than a fixed-size buffer in each call. Particularly if the function is high up the stack or recursive.

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