The pre-processor for GCC will define the macro __GNUC__, so by testing 
for this, one can tell if the GNU compiler was used. Can anyone tell me 
a macro which an IBM compiler will define, so I can test for an IBM 
compiler?

dave



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Dave schrieb:
> The pre-processor for GCC will define the macro __GNUC__, so by testing 
> for this, one can tell if the GNU compiler was used. Can anyone tell me 
> a macro which an IBM compiler will define, so I can test for an IBM 
> compiler?

I'm not aware a specific macro of this kind exists.
The configuration file (/etc/vac.cfg) usually defines stuff like

-D_AIX,-D_AIX32,-D_AIX41,-D_AIX43,-D_AIX50,-D_AIX51,-D_AIX52,-D_AIX53,-D_IBMR2,-D_POWER

so you might use sth like
#if defined(_AIX) && !defined(__GNUC__)

However, with my humble self-written stuff I almost never
found it necessary to distinguish between different compilers
for the same platform. C and possibly C++ as well are so well
standardized these days that it almost makes no difference
as far as source code is concerned.
The latest IBM compilers even have switches and options
mimicking those of their gcc counterparts.

Michael Kraemer wrote:
> Dave schrieb:
>> The pre-processor for GCC will define the macro __GNUC__, so by 
>> testing for this, one can tell if the GNU compiler was used. Can 
>> anyone tell me a macro which an IBM compiler will define, so I can 
>> test for an IBM compiler?
> 
> I'm not aware a specific macro of this kind exists.
> The configuration file (/etc/vac.cfg) usually defines stuff like
> 
> -D_AIX,-D_AIX32,-D_AIX41,-D_AIX43,-D_AIX50,-D_AIX51,-D_AIX52,-D_AIX53,-D_IBMR2,-D_POWER 
> 
> 
> so you might use sth like
> #if defined(_AIX) && !defined(__GNUC__)

Thank you.

> However, with my humble self-written stuff I almost never
> found it necessary to distinguish between different compilers
> for the same platform. C and possibly C++ as well are so well
> standardized these days that it almost makes no difference
> as far as source code is concerned.
> The latest IBM compilers even have switches and options
> mimicking those of their gcc counterparts.
> 

If I was writing the code myself from scratch, I would not be worrying 
about this. Unfortunately, the Sage project (you see my other note) has 
code from many sources, some of which does things like pass flags 
directly to the linker. The options for building shared libraries in 
particular vary somewhat.




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