A code snippet shows how to use Tls callback in VC++

TlsCallback.cpp

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

VOID NTAPI MyCallback(PVOID handle, DWORD reason, PVOID resv);

#pragma data_seg(".CRT$XLB")
PIMAGE_TLS_CALLBACK tls_entry = MyCallback;
#pragma data_seg()

#pragma comment(linker, "/INCLUDE:__tls_used")
#pragma comment(linker, "/INCLUDE:_tls_entry")


VOID NTAPI MyCallback(PVOID handle, DWORD reason, PVOID resv)
{
    if (reason == DLL_PROCESS_ATTACH) {
        printf("DLL_PROCESS_ATTACH\n");
    } else if (reason == DLL_PROCESS_DETACH) {
        printf("DLL_PROCESS_DETACH\n");
    }
}

int main() {
    printf("main\n");
    return 0;
}