winmemory.c

#include <stdio.h>
#include <Windows.h>

static char error_message[1024];

static char *StrGetLastError(DWORD error_code)
{
    LPSTR messageBuffer = NULL;

    FormatMessageA(FORMAT_MESSAGE_ALLOCATE_BUFFER |
                   FORMAT_MESSAGE_FROM_SYSTEM |
                   FORMAT_MESSAGE_IGNORE_INSERTS,
                   NULL,
                   error_code,
                   MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT),
                   (LPSTR) &messageBuffer,
                   0,
                   NULL);

    strncpy(error_message, messageBuffer, sizeof(error_message) - 1);
    LocalFree(messageBuffer);

    return error_message;
}

int main(void)
{
    LPVOID ptr = VirtualAlloc(NULL, 24, MEM_COMMIT | MEM_RESERVE, PAGE_READWRITE);
    if (ptr == NULL) {
        fprintf(stderr, "VirtualAlloc: %s\n", StrGetLastError(GetLastError()));
        return 1;
    }
    DWORD oldFlProtect;
    BOOL status = VirtualProtect(ptr, 24, PAGE_READONLY, &oldFlProtect);
    if (!status) {
        fprintf(stderr, "VirtualProtect: %s\n", StrGetLastError(GetLastError()));
        return 1;
    }
    status = VirtualFree(ptr, 0, MEM_RELEASE);
    if (!status) {
        fprintf(stderr, "VirtualFree: %s\n", StrGetLastError(GetLastError()));
        return 1;
    }
    return 0;
}