Can I disable a macro in an inner function?

Question

Possible Duplicate:
Can I redefine a C++ macro then define it back?

I have an application that calls a function from a third party SDK lots of times along the app lifetime. This third party function checks for some errors with its _3RDPARTY_ASSERT (which is a wrapper around _ASSERT).

My problem is that in one of these calls, I sometimes expect an error (and handle it afterwards). I would like to disable the assert in this case, as it's quite annoying while debugging, but keep it in all the other cases.

I have tried to handle it with pragma push_macro/pop_macro but I haven't found a way. Is this possible?

I have the source of 3rdParty.cpp but would prefer not to touch it.

This would be a simplified version of the code:

mine.cpp:

#include "3rdparty.h"

HRESULT MyMethod(...)
{
    HRESULT hr;
    hr = _3rdParty(...);
    if (SUCCEEDED(hr))
        hr = _3rdParty(...);
    if (SUCCEEDED(hr))
        hr = _3rdParty(...);
    ...    
    if (SUCCEEDED(hr))
        hr = _3rdParty(...); // This call shouldn't throw the assertion, as I expect it to fail sometimes!
    if (FAILED(hr))
        doSomething();
    else
        doSomethingElse();
    ...
    if (SUCCEEDED(hr))
       hr = _3rdParty(...);
    return hr;    
}

3rdParty.cpp:

...
#define _3RDPARTY_ASSERT (_ASSERT)
...
HRESULT _3rdParty(...)
{
    HRESULT hr;
    hr = SomeFunction();
    _3RDPARTY_ASSERT(SUCCEEDED(hr));
    return hr;
}

@Jon: It's not a duplicate. That question is about the general case, with a relatively simple solution, and this is about a specific case with no obvious solution. — raven, Dec 04 '12 at 10:10

score 2 · Accepted Answer · answered Dec 04 '12 at 10:05

2

The problem here is that unless it is inlined, the function will be tokenized and compiled a single time. This means it doesn't matter if the macro is defined or not when you call the function, only when it is compiling the function itself.

answered Dec 04 '12 at 10:05

Agentlien

4,996
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I know that... I was hoping there was some kind of workaround :) – raven Dec 04 '12 at 10:06
Since you want to change how the function is defined, but only at one specific call, I don't really see how. Sorry. Is there no other way you can handle this first and then save the error info for processing later? – Agentlien Dec 04 '12 at 10:08
I don't think so. I could add a _3rdParty_NoAssert() with the exact same code but without the assert. I'm trying to avoid that, though. – raven Dec 04 '12 at 10:15
1

Them I'm afraid I don't see a solution to your problem. – Agentlien Dec 04 '12 at 10:17

score 1 · Answer 2 · answered Dec 04 '12 at 10:08

1

If you have access to the definition of _3RDPARTY_ASSER, like

#define _3RDPARTY_ASSERT definition

Then you save that definition:

#define SAVE_ASSERT definition

Then in the place in your code when you don't want an assertion you could #undef _3RDPARTY_ASSERT or #define it to something else.

After that code you can re-enable the old definition by

#define _3RDPARTY_ASSERT SAVE_ASSERT

A second solution, which I prefer, is this: If you have access to the 3'd party code, you can create another version of _3rdParty(...) which doesn't assert, then use it as needed.

answered Dec 04 '12 at 10:08

Israel Unterman

13,158
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1

Except he wants to disable it within a call, not where the macro is specified itself, so redefining the macro at that point won't make a difference. Your second solution, however, seems reasonable. – Agentlien Dec 04 '12 at 10:10
Thanks! As Agentlien stated, the first part is not useful for my specific problem. I fear I will have to create another version of the method... – raven Dec 04 '12 at 10:24

Can I disable a macro in an inner function?

2 Answers2