[CMake] try using the "-03" option to gcc

[Water Lin]

Michael Wild <themiwi at gmail.com> writes:

> On 23. Dec, 2009, at 9:56 , Water Lin wrote:
>
>> Michael Wild <themiwi at gmail.com> writes:
>> 
>>> On 23. Dec, 2009, at 9:22 , Water Lin wrote:
>>> 
>>>> 
>>>> I am trying to use the "-03" option to gcc. But after I use
>>>> --------------------
>>>> add_definitions(-03)
>>>> --------------------
>>>> 
>>>> in CMakeLists.txt file and generate the Makefile, I make the project and
>>>> gcc provides me a info:
>>>> -----------
>>>> c++: unrecognized option '-03'
>>>> -----------
>>>> 
>>>> How can I add "-03" option by CMakeLists.txt?
>>>> 
>>>> Thanks
>>>> 
>>>> Water Lin
>>> 
>>> That's because the options is not called -03 ("dash zero three") but -O3 ("dash big-ooh three").
>>> 
>>> And you shouldn't do that anyways. Rather set the CMAKE_BUILD_TYPE option to "Release" in your cache (NOT the CMakeLists.txt file). E.g. if you're using the command line:
>>> 
>>> cmake -DCMAKE_BUILD_TYPE=Release /path/to/source
>> 
>> Do you mean that if I set -DCMAKE_BUILD_TYPE=Release, I will get the -O3
>> option?
>> 
>> I tried it, it seems work that way. But while I run my code, it will get
>> a segmentation fault.
>> 
>> Is this the correct way?
>> 
>> Thanks
>> 
>> Water Lin
>
> Well, the segmentation fault is almost surely a programming error and nothing that CMake (close to impossible) or your compiler (very unlikely, but possible) caused. Does the program run if you don't use -O3? That usually indicates that you are messing with your memory (i.e. writing/reading past array boundaries, referring to deallocated objects/variables, etc.). On Linux you can use the tool called valgrind to find such errors.
>
> Michael

Thanks a lot for you detail descriptions.

I think there is some potential error in my program. I will check it.

Thanks

Water Lin

>
>

-- 
Water Lin's notes and pencils: http://en.waterlin.org
Email: WaterLin at ymail.com
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