How to specify gcc flags (CXXFLAGS) particularly for a specific module?

Question

I am building a new NS3 module recently. In my code, I use something new features of the C++11 (c++0x), I want to add a gcc flags (CXXFLAGS) "-std=c++0x" to the waf configuration system.

I tried to this: CXXFLAGS="-std=c++0x" waf configure, and then build it. However, it turns out that some of the exsiting modules such as ipv4-address is not compatible to c++11. Thus, I want to specify this flag particularly for my new module so that other modules won't be complied on c++11.

I tried to add this to the wscript in my new module:

def configure(conf):
    conf.env.append_value('CXXFLAGS', '-std=c++0x')

It fails as the first trial.

How can I do that?

Dagny

Doesn't adding -std=c++0x in configure sets it globally? – Spontaneous

Answer 1

Although @drahnr's answer is correct for vanilla waf, it won't work with NS-3's build system, which is apparently what OP wants. To add CXXFLAGS to an NS-3 program, you can add them to the build object instead of in the configuration stage.

For example:

def build(bld):   
    obj = bld.create_ns3_program('my_app', ['core', 'other-dependencies'])
    obj.source = 'MyApplication.cpp'
    obj.cxxflags = ['-std=c++11']

Ivonneivor

Answer 2

According to the waf book 1.7.8, section 10.1.1 and 10.1.2

    bld.shlib(source='main.c',
            target='myshlib',
            cflags       = ['-O2', '-Wall'], 
            cxxflags     = ['-O3', '-std=c++0x'],
            use          = 'myobjects')

    bld.objects(source='ip4.c',
            cflags       = ['-O2', '-Wall'], 
            cxxflags     = ['-std=somethingelse'],
            target       = 'myobjects')

Note #1 - this code is composed of the 2 examples provided in the wafbook and not tested at all.

Note #2 - you may need to make waf aware of 'myobjects' generated or they may not be used to build 'myshlib', as waf indexes all files before building.

Casandracasanova

but the NS3 waf system is so complicated that they organize the source and targets not in this manner... – Dagny