Understanding memory allocation, test program crashing

Question

I am just about finished reading K&R, and that is all the C that I know. All my compilation is done from Windows command line using MinGW, and I have no knowledge of ad

Answer 1

The memory you are allocating via the recursive functional calls is allocated from the stack. All of the stack memory must be contiguous. When your process starts a thread, Windows will reserve a range of virtual memory address space for that thread's stack. The amount of memory to be reserved is specified in your EXE file's "PE header." PE stands for "Portable Executable."

Using the dumpbin utility included with Visual Studio, with itself (dumpbin.exe) as the input file:

dumpbin /headers dumpbin.exe

... there is some output, and then:

      100000 size of stack reserve
        2000 size of stack commit

The "100000" is a hexadecimal number equal to 1,048,576, so this represents around 1MB.

In other words, the operating system will only reserve a 1MB address range for the stack. When that address range is used up, Windows may or may not be able to allocate further consecutive memory ranges to increase the stack. The result depends on whether further contiguous address range is available. It is very unlikely to be available, due to the other allocations Windows made when the thread began.

To allocate a maximum amount of virtual memory under Windows, use the VirtualAlloc family of functions.