Question

I’m trying to build simplest Boost.Asio tutorial example "timer1" (it’s in timer.cpp) with waf on Debian squeeze, python 2.6.6.

root@ds:/var/timer# ls

timer.cpp wscript

wscript here is a config of waf:

#! /usr/bin/env python
top = '.'
out = '.'

def options(opt):
    opt.load('compiler_cxx')

def configure(conf):
    conf.load('compiler_cxx')
    conf.env['LINKFLAGS'] = '--verbose -L/usr/local/lib -lboost_system'

def build(bld):
    tgen = bld.new_task_gen()
    tgen.features = 'cxx cxxprogram'
    tgen.source = 'timer.cpp'
    tgen.target = 'timer'
    tgen.includes = '.'
    tgen.update_outputs = True

waf configure is successfull.

But waf --verbose build finishes with error (I inserted <*> below to mark a line)

Waf: Entering directory `/var/timer'
[1/2] cxx: timer.cpp -> timer.cpp.1.o
[2/2] cxxprogram: timer.cpp.1.o -> timer
timer.cpp.1.o: In function `__static_initialization_and_destruction_0(int, int)':
timer.cpp:(.text+0x103): undefined reference to `boost::system::generic_category()'
timer.cpp:(.text+0x10f): undefined reference to `boost::system::generic_category()'
...
Build failed
-> task in 'timer' failed (exit status 1): 
{task 38446736: cxxprogram timer.cpp.1.o -> timer}
<*>
['/usr/bin/g++', '--verbose -L/usr/local/lib -lboost_system', 'timer.cpp.1.o', '-o', '/var/timer/timer', '-Wl,-Bstatic', '-Wl,-Bdynamic']    

It seems gcc called by waf didn’t find boost_system library during linkage.

But everything works fine if I build example by gcc without waf.

root@ds:/var/timer# /usr/bin/g++ --verbose -I/var/flake/lib/boost timer.cpp -c -o timer.cpp.1.o
...
<**>
root@ds:/var/timer# /usr/bin/g++ --verbose -L/usr/local/lib -lboost_system timer.cpp.1.o -o timer -Wl,-Bstatic -Wl,-Bdynamic   
...
root@ds:/var/timer# ls
timer.cpp  timer.cpp.1.o  timer  wscript

As you can see command line used by waf (marked by <*> ) is identical with command line marked by <**>. But the result is completely different. Why? And how can I force waf to build that thing? Solution from here doesn’t work for me too. Also tried

...
opt.tool_options('boost')
...
conf.load('compiler_cxx boost')
conf.check_boost()
...
tgen.uselib = 'BOOST'
...

but without any effect

And another question. Output of gcc --verbose is much more extensive than output of waf --verbose. It seemed to me that verbose option must force waf to display all such info. Why isn’t that true? waf option -vvv doesn’t display this info as well.

Answer 1

If you use the boost tool, you should check the waf boost example in playground/boost, and you will see that check_boost takes arguments. It will solve your issue.

Alternatively if you don’t use the tool, and using a real OS where libraries are set up in an accessible folder, you can just do:

conf.env.LIB_BOOST = ['boost_system']

...

bld(
 ...,
 use='BOOST',
 ...,
)

Note for your future scripts:

• avoid using CFLAGS, CXXFLAGS, LINKFLAGS as it’s not portable.
• don’t set out=’.’ if possible
• use bld(…) vs. the old syntax