我正在尝试添加锁定 SAL 语句以在我的应用程序中查找/防止错误锁定。就像缺少锁定调用和不匹配的锁定调用一样。我收到了我不明白的警告。我已将它们作为注释放在下面的示例中。我打开了代码分析并设置了 Microsoft All Rules。我正在使用 Visual Studio 2019 16.11.9。我也尝试过 Visual Studio 2022 17.0.5 并得到相同的结果。
我已经尝试用_Success_ 代替_When_。我尝试返回 bool 而不是 BOOL 和 _Success_(return) vs _Success_(return != 0)。
我读过的一些研究：
https://docs.microsoft.com/en-us/cpp/code-quality/c26135?view=msvc-170
_When_(return != 0, _Acquires_lock_(p->cs))
int TryEnter(DATA* p)
{
if (p->state != 0)
{
EnterCriticalSection(&p->cs);
return p->state;
}
return 0;
}
前一篇文章来自 2021 年，因此可能比后一篇适用于 Visual Studio 2015 的文章更新。VS2015 示例无法按原样运行；_Success_ 注释似乎已更改，因为它不再需要两个参数。
// Incorrect
_Success_(return == TRUE, _Acquires_lock_(*lpCriticalSection))
BOOL WINAPI TryEnterCriticalSection(
_Inout_ LPCRITICAL_SECTION lpCriticalSection
);
// Correct
_Success_(return != 0, _Acquires_lock_(*lpCriticalSection))
BOOL WINAPI TryEnterCriticalSection(
_Inout_ LPCRITICAL_SECTION lpCriticalSection
);
我的测试代码：
#define _WIN32_WINNT _WIN32_WINNT_WIN7
#include <windows.h>
#include <tchar.h>
// https://docs.microsoft.com/en-us/cpp/code-quality/c26135?view=msvc-170
class CLock {
public:
CLock() noexcept : m_hMutex(CreateMutex(nullptr,FALSE,nullptr)){
}
~CLock(){
CloseHandle(m_hMutex);
m_hMutex = nullptr;
}
_When_(return != 0, _Acquires_lock_(this->m_hMutex)) BOOL Lock() noexcept {
// warning C26135: Missing annotation _Acquires_lock_(this->m_hMutex) at function 'CLock::Lock'.
// I don't understand this warning, I have the annotation?
return (WaitForSingleObject(m_hMutex,INFINITE) == WAIT_OBJECT_0);
}
_When_(return != 0, _Releases_lock_(this->m_hMutex)) BOOL Unlock() noexcept {
// warning C26135 : Missing annotation _Releases_lock_(this->m_hMutex) at function 'CLock::Unlock'.
// I don't understand this warning, I have the annotation?
return ReleaseMutex(m_hMutex);
}
private:
// Ensure no copies can be made
CLock(const CLock &lCopy) = delete;
CLock(const CLock &&lMove) = delete;
const CLock &operator=(const CLock &lCopy) = delete;
const CLock &&operator=(const CLock &&lMove) = delete;
_Has_lock_kind_(_Lock_kind_mutex_) HANDLE m_hMutex;
};
class ThreadedThingy {
public:
ThreadedThingy() noexcept : m_iThingy(0){
}
VOID TestBadNotLocked() noexcept {
// warning C26130: Missing annotation _Requires_lock_held_(this->m_lLock) or _No_competing_thread_
// at function 'ThreadedThingy::TestBadNotLocked'. Otherwise it could be a race
// condition. Variable 'this->m_iThingy' should be protected by lock 'this->m_lLock'.
// This should be a warning since the lock isn't held
m_iThingy = 10;
}
VOID TestBadNotUnlocked() noexcept {
if (m_lLock.Lock()){
// warning C26165: Possibly failing to release lock '(&this->m_lLock)->m_hMutex' in function
// 'ThreadedThingy::TestBadNotUnlocked'.
// This should be a warning since lock isn't unlocked
// warning C26130: Missing annotation _Requires_lock_held_(this->m_lLock) or _No_competing_thread_
// at function 'ThreadedThingy::TestBadNotUnlocked'. Otherwise it could be a race
// condition. Variable 'this->m_iThingy' should be protected by lock 'this->m_lLock'.
// I don't understand this warning, the lock is held
m_iThingy = 20;
}
}
VOID TestGood() noexcept {
if (m_lLock.Lock()){
// warning C26130: Missing annotation _Requires_lock_held_(this->m_lLock) or _No_competing_thread_ at
// function 'ThreadedThingy::TestGood'. Otherwise it could be a race condition.
// Variable 'this->m_iThingy' should be protected by lock 'this->m_lLock'.
// I don't understand this warning, the lock is held
m_iThingy = 20;
// warning C26165: Possibly failing to release lock '(&this->m_lLock)->m_hMutex' in function
// 'ThreadedThingy::TestGood'.
// I kind of understand this warning because Unlock can't gaurentee the lock is released
m_lLock.Unlock();
}
}
private:
_Has_lock_kind_(_Lock_kind_mutex_) CLock m_lLock;
_Guarded_by_(this->m_lLock) INT m_iThingy;
};
INT _tmain() noexcept {
ThreadedThingy ttTest;
ttTest.TestBadNotLocked();
ttTest.TestBadNotUnlocked();
ttTest.TestGood();
return 0;
}
谢谢！
-丹尼尔