How alloca() Allocates Stack Memory Without Skipping the Guard Page

How do functions like alloca allocate memory from the stack?

In this post, Raymond Chen explains how the `_alloca()` function allocates memory from the stack on x86-64, specifically addressing whether it performs the necessary stack probing via `_chkstk()`. He confirms that `_alloca()` calls `_chkstk()` to probe the stack before adjusting the stack pointer, just like the compiler does for large local frames. A code example illustrates the assembly instructions, showing the same `__chkstk` function used for both the initial frame setup and the `alloca()` allocation.