[RESOLVED] Defining a macro to disable warnings with pragma

[Mybowlcut]

Hey.

I want to do this:

#ifndef DISABLE_WARNING_H
#define DISABLE_WARNING_H

#define PUSH_DISABLE_WARNING(warning)
#pragma warning(push)
#pragma warning(disable : 4800)

#define POP_DISABLE_WARNING()
#pragma warning(pop)

#endif

But it's clearly not working... it was a quick attempt since I know that I don't have a clue on how to code it...

Any help?

Cheers.

[_Superman_]

For #define, a new line is the terminating character.
So put a backslash to indicate that the line continues to the next.

#ifndef DISABLE_WARNING_H
#define DISABLE_WARNING_H

#define PUSH_DISABLE_WARNING(warning) \
#pragma warning(push) \
#pragma warning(disable : 4800)

#define POP_DISABLE_WARNING() \
#pragma warning(pop)

#endif

[Kheun]

_Superman_, the problem is not about writing a macro but on using preprocessor to suppress warning messages from the compiler on certain part of the code. One example would be reusing a legacy code that causing the compiler to generate warning message. As just any good programmer, we must not ignore the compiler warning. However, since you may not have the right to change the legacy code, you only want to suppress the compiler warning from the legacy code but from other part of the code.

[Peter_APIIT]

I looking for a standard approach rather than platform specific.

Thanks.

[Amleto]

it's ide specific, not platform specific, right?

[_Superman_]

I have done this many times and it did work.

This is what I do.

#pragma warning(disable:4800)

Some code or #include which throws the warning.

#pragma warning(default:4800)

[Peter_APIIT]

it's ide specific, not platform specific, right?

I looking for standard approach rather than compiler/IDE specific.

Does boost offer this kind of feature ?

Thanks.

[Kheun]

I doubt so. As far as I know, #pragma preprocessor directive is compiler specific. I don't think it is part of the C++ language.

[Mybowlcut]

For #define, a new line is the terminating character.
So put a backslash to indicate that the line continues to the next.

#ifndef DISABLE_WARNING_H
#define DISABLE_WARNING_H

#define PUSH_DISABLE_WARNING(warning) \
#pragma warning(push) \
#pragma warning(disable : 4800)

#define POP_DISABLE_WARNING() \
#pragma warning(pop)

#endif

Hey. I tried that and get errors:

#define PUSH_DISABLE_WARNING(warning_) \
#pragma warning(push) \
#pragma warning(disable : warning_)

#define POP_DISABLE_WARNING() \
#pragma warning(pop)

int main(int argc, char* argv[])
{
  return 0;
}

Error	1	error C2162: expected macro formal parameter	c:\documents and settings\bill\my documents\visual studio 2005\projects\test\test\main.cpp	2
Error	2	error C2162: expected macro formal parameter	c:\documents and settings\bill\my documents\visual studio 2005\projects\test\test\main.cpp	3

_Superman_, the problem is not about writing a macro but on using preprocessor to suppress warning messages from the compiler on certain part of the code. One example would be reusing a legacy code that causing the compiler to generate warning message. As just any good programmer, we must not ignore the compiler warning. However, since you may not have the right to change the legacy code, you only want to suppress the compiler warning from the legacy code but from other part of the code.

Not quite sure what you meant to say here, as the problem is indeed how to write a macro that suppresses warning messages.

Cheers.

[Kheun]

Thanks for clearing up.

I found this link that may help but I haven't tried it.
http://msdn.microsoft.com/en-us/library/d9x1s805.aspx

[Mybowlcut]

Thanks for the link. I appear to be using it correctly, so I think my macro is coded wrong. From the MSDN link:

#pragma warning( push )
#pragma warning( disable : 4705 )
#pragma warning( disable : 4706 )
#pragma warning( disable : 4707 )
// Some code
#pragma warning( pop )

[Amleto]

i think its expecting the thing after # in #pragma to be a macro argument. I dont know much about macros, but # and ## are used for token pasting and things like that.

try this:

#define myPragma (#pragma)

#define PUSH_DISABLE_WARNING(warning_) \
myPragma warning(push)\
myPragma warning(disable : warning_)

#define POP_DISABLE_WARNING() \
#pragma warning(pop)

int main(int argc, char* argv[])
{
  return 0;
}

don't know why it's not needed for the warning (pop) part though. I believe it is because no argument is given to the macro..

[Peter_APIIT]

I doubt so. As far as I know, #pragma preprocessor directive is compiler specific. I don't think it is part of the C++ language.

Although there aren't any language feature support it, but i think [preprocessor if] should be able to cope with it.

[Mybowlcut]

i think its expecting the thing after # in #pragma to be a macro argument. I dont know much about macros, but # and ## are used for token pasting and things like that.

try this:

#define myPragma (#pragma)

#define PUSH_DISABLE_WARNING(warning_) \
myPragma warning(push)\
myPragma warning(disable : warning_)

#define POP_DISABLE_WARNING() \
#pragma warning(pop)

int main(int argc, char* argv[])
{
  return 0;
}

don't know why it's not needed for the warning (pop) part though. I believe it is because no argument is given to the macro..

Sorry for the late reply. Your code doesn't compile for me:

#define myPragma (#pragma)

#define PUSH_DISABLE_WARNING(warning_) \
myPragma warning(push) \
myPragma warning(disable : warning_)

#define POP_DISABLE_WARNING() \
#pragma warning(pop)

PUSH_DISABLE_WARNING(4800)

bool f()
{
    unsigned short x = 32;
    return x;
}

POP_DISABLE_WARNING()

int main(int argc, char* argv[])
{
  return 0;
}

Error	1	error C2121: '#' : invalid character : possibly the result of a macro expansion	c:\documents and settings\bill\my documents\visual studio 2005\projects\test\test\main.cpp	10
Error	2	error C2146: syntax error : missing ';' before identifier 'warning'	c:\documents and settings\bill\my documents\visual studio 2005\projects\test\test\main.cpp	10
Error	3	error C4430: missing type specifier - int assumed. Note: C++ does not support default-int	c:\documents and settings\bill\my documents\visual studio 2005\projects\test\test\main.cpp	10
Error	4	error C2065: 'push' : undeclared identifier	c:\documents and settings\bill\my documents\visual studio 2005\projects\test\test\main.cpp	10
Error	5	error C4430: missing type specifier - int assumed. Note: C++ does not support default-int	c:\documents and settings\bill\my documents\visual studio 2005\projects\test\test\main.cpp	10
Error	6	error C2143: syntax error : missing ';' before '('	c:\documents and settings\bill\my documents\visual studio 2005\projects\test\test\main.cpp	10
Error	7	error C2121: '#' : invalid character : possibly the result of a macro expansion	c:\documents and settings\bill\my documents\visual studio 2005\projects\test\test\main.cpp	10
Error	8	error C2059: syntax error : ')'	c:\documents and settings\bill\my documents\visual studio 2005\projects\test\test\main.cpp	10
Error	9	error C2146: syntax error : missing ')' before identifier 'warning'	c:\documents and settings\bill\my documents\visual studio 2005\projects\test\test\main.cpp	10
Error	10	error C2146: syntax error : missing ';' before identifier 'warning'	c:\documents and settings\bill\my documents\visual studio 2005\projects\test\test\main.cpp	10
Error	11	error C4430: missing type specifier - int assumed. Note: C++ does not support default-int	c:\documents and settings\bill\my documents\visual studio 2005\projects\test\test\main.cpp	10
Error	12	error C2086: 'int pragma' : redefinition	c:\documents and settings\bill\my documents\visual studio 2005\projects\test\test\main.cpp	10
Error	13	error C2065: 'disable' : undeclared identifier	c:\documents and settings\bill\my documents\visual studio 2005\projects\test\test\main.cpp	10
Error	14	error C2143: syntax error : missing ')' before ':'	c:\documents and settings\bill\my documents\visual studio 2005\projects\test\test\main.cpp	10
Error	15	error C2448: 'warning' : function-style initializer appears to be a function definition	c:\documents and settings\bill\my documents\visual studio 2005\projects\test\test\main.cpp	10
Error	16	error C2059: syntax error : 'constant'	c:\documents and settings\bill\my documents\visual studio 2005\projects\test\test\main.cpp	10
Error	17	error C2059: syntax error : ')'	c:\documents and settings\bill\my documents\visual studio 2005\projects\test\test\main.cpp	10
Error	18	error C2143: syntax error : missing ';' before '{'	c:\documents and settings\bill\my documents\visual studio 2005\projects\test\test\main.cpp	13
Error	19	error C2447: '{' : missing function header (old-style formal list?)	c:\documents and settings\bill\my documents\visual studio 2005\projects\test\test\main.cpp	13
Error	20	error C2121: '#' : invalid character : possibly the result of a macro expansion	c:\documents and settings\bill\my documents\visual studio 2005\projects\test\test\main.cpp	18
Error	21	error C2146: syntax error : missing ';' before identifier 'warning'	c:\documents and settings\bill\my documents\visual studio 2005\projects\test\test\main.cpp	18
Error	22	error C4430: missing type specifier - int assumed. Note: C++ does not support default-int	c:\documents and settings\bill\my documents\visual studio 2005\projects\test\test\main.cpp	18
Error	23	error C2086: 'int pragma' : redefinition	c:\documents and settings\bill\my documents\visual studio 2005\projects\test\test\main.cpp	18
Error	24	error C2065: 'pop' : undeclared identifier	c:\documents and settings\bill\my documents\visual studio 2005\projects\test\test\main.cpp	18
Error	25	error C2448: 'warning' : function-style initializer appears to be a function definition	c:\documents and settings\bill\my documents\visual studio 2005\projects\test\test\main.cpp	20

[Amleto]

this might help explain why:
http://bytes.com/groups/net-vc/28438...acro-expansion