[Scons-users] Request help on the usage of scons

[Bill Deegan]

or
object_nodelist = env.Object('src/sample.c', CFLAGS='$CFLAGS
-Wno-conversion')

Should work (I think).


On Wed, Sep 7, 2022 at 7:57 AM Daniel Moody <dmoody256 at gmail.com> wrote:

> setting the specific flag on the invocation of the specific builder would
> be the recommended way to do this:
>
> object_nodelist = env.Object('src/sample.c', CFLAGS=env.get('CFLAGS',
> []) + ['-Wno-conversion'])
>
> But assuming this is for some reason not possible, there are other
> roundabout ways to do this. I am also assuming you only have access to the
> environment? One thing you could do is create a generator that expands to
> one or the other depending on the source file. Here is an example:
>
> def cflags_warn_conversion(env, source, target, for_signature):
>     if source[0].abspath == env.File('#src/sample.c').abspath:
>         return '-Wno-conversion'
>     else:
>         return '-Wconversion'
>
> env['CFLAGS_WARN_CONVERSION_GEN'] = cflags_warn_conversion
> env.Append(CFLAGS=['$CFLAGS_WARN_CONVERSION_GEN'])
>
> What this is doing is putting a function in the CFLAGS to run when
> evaluating an expansion, when the CFLAGS is being evaluated to execute a
> command line, scons will perform expansion on any $ variables, and so the
> source file would be identified and the correct command line flag would be
> added to the command line.
>
>
> On Wed, Sep 7, 2022 at 3:25 AM David Zhu via Scons-users <
> scons-users at scons.org> wrote:
>
>> Dear scons community,
>>
>> Sorry for bothering.
>>
>> I have a question about the usage of scons.
>>
>> Firstly, I want to explain my requirement by makefile.
>>
>> In makefile, I can configure the CFLAGS for a specific C source file
>> without changing other parts of the build script.
>>
>> For example, I add below line in makefile to apply '-Wno-conversion' for
>> 'src/sample.c'.
>>
>> ----------
>>
>> src/sample.o: CFLAGS += -Wno-conversion
>>
>> ----------
>>
>> The reason is that '-Wconversion' is configured for all source files but
>> I want to remove the conversion check for 'src/sample.c' only.
>>
>> So my question is how to configure that in scons?
>>
>> In my project, I can only edit the script in a small range. I cannot use
>> 'env.Object' to generate 'sample.o' in this range.
>>
>> 'env.Object' must be called in the next step by another script shared by
>> all modules.
>>
>> Many thanks for your help!
>>
>> Best Regards,
>>
>> David
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>> Scons-users mailing list
>> Scons-users at scons.org
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>>
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