Give a name to a boost thread?

Question

Is it possible to give a name to a boost::thread so that the debuggers tables and the crash logs can be more readable? How?

Antacid

Answer 1

You would need to access the underlying thread primitive and assign a name in a system dependent manner. Debugging and crash logs are inherently system dependent and boost::thread is more about non-system-dependency, i.e. about portability.

It seems ( http://www.boost.org/doc/libs/1_43_0/doc/html/thread.html ) that there is no documented way to access underlying system resources for a boost thread. (But I have never used it myself so I may miss something.)

Edit: (As David writes in the comment) http://www.boost.org/doc/libs/1_43_0/doc/html/thread/thread_management.html#thread.thread_management.thread.nativehandle

Rosetterosewall

+1, boost::thread has a native_handle method that can be used to retrieve the native API handle of the thread. You would need to dig into the thread library to know what is the particular type that it returns and the API documentation on how to use that handle to give it a name... – Perpetrate

For Linux: #778585 – Antacid

For Windows: #906376 – Antacid

For Mac OS X: #2058460 – Antacid

"... in a system dependent manner" The same goes for doing anything to a thread using the system API e.g. creating it. The point of boost is to wrap these various platform-dependent APIs in a single portable API. As you say, "boost::thread is ... about portability". This is an argument in FAVOR of boost having a "set thread name" method. – Kwabena

Answer 2

I'm using boost 1.50.0 on Win32 + VS2010 and thread::native_handle contains number which I didn't manage to pair to anything in system. On the other hand, the thread::get_id() method returns directly windows thread ID in form of a hexadecimal string. Notice that the value returned is platform specific, though. The following code does work under Boost 1.50.0 + Win32 + VS2010. Parts of code reused from msdn

const DWORD MS_VC_EXCEPTION = 0x406D1388;
#pragma pack(push, 8)
typedef struct THREADNAME_INFO {
    DWORD dwType; // Must be 0x1000.
    LPCSTR szName; // Pointer to name (in user addr space).
    DWORD dwThreadID; // Thread ID (-1=caller thread).
    DWORD dwFlags; // Reserved for future use, must be zero.
} THREADNAME_INFO;
#pragma pack(pop)

void _SetThreadName(DWORD threadId, const char* threadName) {
    THREADNAME_INFO info;
    info.dwType = 0x1000;
    info.szName = threadName;
    info.dwThreadID = threadId;
    info.dwFlags = 0;
    __try {
        RaiseException( MS_VC_EXCEPTION, 0, sizeof(info)/sizeof(ULONG_PTR), (ULONG_PTR*)&info );
    }
    __except(EXCEPTION_EXECUTE_HANDLER) {
    }
}
void SetThreadName(boost::thread::id threadId, std::string threadName) {
    // convert string to char*
    const char* cchar = threadName.c_str();
    // convert HEX string to DWORD
    unsigned int dwThreadId;
    std::stringstream ss;
    ss << std::hex << threadId;
    ss >> dwThreadId;
    // set thread name
    _SetThreadName((DWORD)dwThreadId, cchar);
}

Call like this:

boost::thread* thr = new boost::thread(boost::bind(...));
SetThreadName(thr->get_id(), "MyName");

Duckpin

You're missing the THREADNAME_INFO struct and MS_VC_EXCEPTION. Is there no better way to get the number from the boost::thread::id? eek. – Lion

Sorry about that, I've no idea how it happened, should be complete now. As for the thread number - I don't know. Boost docs say there is no way at all... – Duckpin

you can get the thread id by passing GetThreadId (in <Windows.h>) the native handle, which you can get from a boost thread.. From there you can do your RaiseException stuff. GetThreadId is more modern though, you won't be able to run on XP I think. There's also a way to get the private unsigned int out of boost::thread:id if you can't use GetThreadId - but that's seriously evil. – Lion

yes, as is said - using tha native_handle and GetThreadId I got a number which didn't correspond to an application threadId (though it was a valid system threadid). So that didn't work for me. – Duckpin

I meant that threadID obtained was pointing to an existing thread, but not one created by my application. – Duckpin

Answer 3

There is a proposal to add this to boost which has had a slow start: https://github.com/boostorg/thread/issues/84

Hudibrastic