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#include <memory> | |
#include <cassert> | |
#include <Windows.h> | |
struct FileHandle | |
{ | |
::HANDLE fileHandle; | |
//implicit | |
FileHandle(::HANDLE h) noexcept | |
: fileHandle{h} | |
{} | |
//implicit | |
FileHandle(std::nullptr_t = nullptr) noexcept | |
: FileHandle{ INVALID_HANDLE_VALUE } | |
{} | |
operator ::HANDLE() noexcept { return fileHandle; } | |
explicit operator bool() noexcept { return fileHandle != INVALID_HANDLE_VALUE; } | |
}; | |
bool operator== (FileHandle lhs, FileHandle rhs) noexcept | |
{ | |
return lhs.fileHandle == rhs.fileHandle; | |
} | |
bool operator!= (FileHandle lhs, FileHandle rhs) noexcept | |
{ | |
return !(lhs == rhs); | |
} | |
struct FileCloser | |
{ | |
using pointer = FileHandle; | |
void operator()(pointer p) const noexcept | |
{ | |
(void)::CloseHandle(p.fileHandle); | |
} | |
}; | |
using UniqueFile = std::unique_ptr<void, FileCloser>; | |
struct LocalMemoryDeleter | |
{ | |
void operator()(void* p) const noexcept | |
{ | |
(void)::LocalFree(p); | |
} | |
}; | |
using UniqueLocalMemory = std::unique_ptr<void, LocalMemoryDeleter>; | |
int main() | |
{ | |
{ | |
UniqueFile f; | |
assert(f.get().fileHandle == INVALID_HANDLE_VALUE); | |
f.reset(::CreateFile(LR"(.\Bar.txt)", GENERIC_WRITE, {}, {}, OPEN_ALWAYS, FILE_ATTRIBUTE_NORMAL, {})); | |
if (f) | |
{ | |
const unsigned char buffer[] = "hello"; | |
::WriteFile(f.get(), buffer, sizeof(buffer), {}, {}); | |
} | |
} | |
{ | |
const auto h = UniqueLocalMemory{ ::LocalAlloc(LMEM_FIXED, 20) }; | |
*static_cast<int*>(h.get()) = 233; | |
} | |
} |
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