How to change the name of a thread

Question

I have a server application that uses "a lot" of threads. Without wanting to get into an argument about how many threads it really should be using, it would be nice to be able to see some descriptive text in the debugger "threads" window describing what each one is, without having to click through to it and determine from the context what it is.

They all have the same start address so generally the threads window says something like "thread_base::start" or something similar. I'd like to know if there is an API call or something that allows me to customise that text.

Answer 1

Here is the code I use.

This goes in a header file.

#pragma once

#define MS_VC_EXCEPTION 0x406d1388
#pragma warning(disable: 6312)
#pragma warning(disable: 6322)

typedef struct tagTHREADNAME_INFO
{
    DWORD dwType;        // must be 0x1000
    LPCSTR szName;       // pointer to name (in same addr space)
    DWORD dwThreadID;    // thread ID (-1 caller thread)
    DWORD dwFlags;       // reserved for future use, most be zero
} THREADNAME_INFO;

inline
void SetThreadName(DWORD dwThreadID, LPCSTR szThreadName)
{
#ifdef _DEBUG
    THREADNAME_INFO info;
    info.dwType = 0x1000;
    info.szName = szThreadName;
    info.dwThreadID = dwThreadID;
    info.dwFlags = 0;

    __try
    {
        RaiseException(MS_VC_EXCEPTION, 0, sizeof(info) / sizeof(DWORD), (DWORD *)&info);
    }
    __except (EXCEPTION_CONTINUE_EXECUTION)
    {
    }
#else
    dwThreadID;
    szThreadName;
#endif
}

Then I call it like this inside the threads proc.

SetThreadName(GetCurrentThreadId(), "VideoSource Thread");

It is worth noting that this is the exact code that David posted a link to (Thanks! I had forgotten where I got it). I didn't delete this post because I'd like the code to still be available if MSDN decides to reorganize its links (again).

Answer 2

Use SetThreadName