CODEWITHSUNDEEP
c
Rich Jahn
Rich Jahn

Reputation: 443

How can I avoid invalid warning C6011 due to an abort function calling exit()

I am trying to avoid C6011 warning because an abort function is calling exit(). How can I do that?

Here is an example:

#include <stdlib.h>

void abort_function();
void func( int *p );

int main()
{
    int x;

    func( &x );

    return 0;
}

void func( int *p )
{
    if (NULL == p)
        abort_function();

    *p = 5;
}

void abort_function()
{
    exit(0);
}

So this leads to the following warning from PREFast:

warning C6011: Dereferencing NULL pointer 'p': Lines: 17, 18, 20

Simply replacing abort_function() with exit(0) eliminates this warning.

But I'm actually working with a large codebase, and I didn't want to replace all calls to abort_function(). So I was able to eliminate a lot of these warnings by making the function a variadic macro, and temporarily taking out the function definition, like this:

#include <stdlib.h>

#define abort_function( ... ) exit(0);

/*void abort_function();*/
void func( int *p );

int main()
{
    int x;

    func( &x );

    return 0;
}

void func( int *p )
{
    if (NULL == p)
        abort_function();

    *p = 5;
}

#if 0
void abort_function()
{
    exit(0);
}
#endif

This also eliminated the warning, but are there any PREFast options or annotations I could use, to avoid having to modify the code?

Upvotes: 4

Views: 3030

Answers (3)

ugoren
ugoren

Reputation: 16441

In MSVC, defining __declspec(noreturn) for abort_function should do it.
For gcc, __attribute__ ((noreturn)) does the same.

Upvotes: 9

amrith
amrith

Reputation: 973

The reason you are getting this warning is because the compiler doesn't realize that abort_function() will never return. Therefore it believes that there is a legitimate code path where p is NULL; abort_function() is called and returns and then you dereference p.

You can avoid it by either using the (noreturn) declaration or modifying your abort_function() invocation to include a return;

if (p == NULL)
{
    abort_function();
    return;
}

Upvotes: 2

MYMNeo
MYMNeo

Reputation: 836

In C, you can eliminate warnings like this using #pragma. Use it carefully, because you want some warnings. Here is the #pragma for eliminating this warning:

#pragma warning(disable:6011)

Upvotes: 2

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