Question

As of the MSDN spec, CloseHandle throws an Exception if an invalid handle is passed to it when it runs under a debugger.

Since I want to have clean code, I’ve inserted some code to catch it. However, it doesn’t work, the exception gets uncaught.

#include <windows.h>
#include <tchar.h>
#include <exception>
/* omitted code */
CloseHandle(myHandle); // close the handle, the handle is now invalid
try {
    success = CloseHandle(myHandle);
} catch (std::exception& e) {
    _tprintf(TEXT("%s\n"), e.what());
} catch (...) {
    _tprintf(TEXT("UNKNOWN\n"));
}

I get the following two errors from the debugger:

First-chance exception: 0xC0000008: An invalid handle was specified.

Uncaught exception: 0xC0000008: An invalid handle was specified.

I think that the first-chance exception is normal, since it gets fired before the catch statement should get it. However, the uncaught exception makes me wondering what’s actually wrong here.

Answer 1

You have two options:

Option 1:
Use SEH, you need to write something like this:

__try
{
  // closeHandle
}
__except(EXCEPTION_EXECUTE_HANDLER)
{
  // print
}

Option 2:
Use the compiler switch /EHa, which will instruct the compiler to emmit code which will allow you to handle SEH exception via C++ style exception handling:

try
{
 // close handle
}
catch (...)
{
  // print
}

Edit:
Note that CloseHandle() only raises an exception if a debugger is attached to your process.
From the documentation:

If the application is running under a debugger, the function will
throw an exception if it receives either a handle value that is not
valid or a pseudo-handle value.