As @Juul stated Reference types are stored in the Heap and values in the stack. Here is the explanation: Stack and Heap Stack is used for static memory allocation and Heap for dynamic memory allocation, both stored in the computer’s RAM . Variables allocated on the stack are stored directly to the memory, and access … Read more
The shadow space must be provided directly previous to the call. Imagine the shadow space as a relic from the old stdcall/cdecl convention: For WriteFile you needed five pushes. The shadow space stands for the last four pushes (the first four arguments). Now you need four registers, the shadow space (just the space, contents don’t … Read more
Modern operating systems do not give you direct access to hardware RAM and instead abstract it in so called virtual memory, which it maps to RAM on demand. Each process is usually given its own private copy of the complete address space. This allows the OS to move a process’ memory around in RAM at … Read more
The string literal will be allocated in data segment. The pointer to it, a, will be allocated on the stack. Your code will eventually get transformed by the compiler into something like this: #include <stdio.h> const static char literal_constant_34562[7] = {‘t’, ‘e’, ‘s’, ‘a’, ‘j’, ‘a’, ‘\0’}; int main() { char *a; a = &literal_constant_34562[0]; … Read more
_chkstk does stack probes to make sure each page is touched in order after a (potentially) large allocation, e.g. an alloca. Because Windows will only grow the stack one page at a time up to the stack size limit. Touching that “guard page” triggers stack growth. It doesn’t guard against stack overflow; I think you’re … Read more
An array stores its elements in contiguous memory locations. If You created the array locally it will be on stack. Where the elements are stored depends on the storage specification. For Example: An array declared globally or statically would have different storage specification from an array declared locally. Technically, the where part is implementation defined … Read more
Update: gcc8 simplifies this at least for normal use-cases (-fomit-frame-pointer, and no alloca or C99 VLAs that require variable-size allocation). Perhaps motivated by increasing usage of AVX leading to more functions wanting a 32-byte aligned local or array. Except for main in 32-bit code, then it still does the full return address+frame-pointer backtrace-friendly version even … Read more
What’s the difference between kernel stack and user stack ? In short, nothing – apart from using a different location in memory (and hence a different value for the stack pointer register), and usually different memory access protections. I.e. when executing in user mode, kernel memory (part of which is the kernel stack) will not … Read more
as I understand, int is value type and therefore lives in the stack Your understanding is incorrect. Value types are called “value types” because they are copied by value. Reference types are called “reference types” because they are copied by reference. It is not at all true that “value types always live on the stack”. … Read more
Yes, one is on the stack, the other on the heap. There are two important differences: First, the obvious, and less important one: Heap allocations are slow. Stack allocations are fast. Second, and much more important is RAII. Because the stack-allocated version is automatically cleaned up, it is useful. Its destructor is automatically called, which … Read more