[Scons-users] TryAction ('pkgconfig ..') and PRINT_CMD_LINE_FUNC => exception.

[Jos De Laender]

Dear all,

I'm a new and happy user of Scons.
I managed to build and crossbuild a Qt project of mine using Scons, 
something I didn't manage with CMake.

However, now lately I'm experiencing a strange and nasty issue.
I read about already on Google, but neither do I find the solution, nor 
can I solve it myself.

I have a detector for pkg-config, along the lines of what's on the wiki.

When I install then also a PRINT_CMD_LINE_FUNC, (and remove the .db 
stuff) I get an exception error in config.log (and the test fails).

The really weird thing is that I have no issue as long as I don't write 
anything to stdout in PRINT_CMD_LINE_FUNC
Thus writing the command to a file within PRINT_CMD_LINE_FUNC and 
returning works. As soon as I write something to stdout (via print, sys 
...) the issue occurs.

Also, when I postpone install of PRINT_CMD_LINE_FUNC until after the 
pkg-config checks, I have no single issue on a complete build.

I don't get it ... (and I'm new to python as well).

Clues ?

My Scons :

/usr/local/bin/scons
jos at debian:~/dlEmu8080$ scons --version
SCons by Steven Knight et al.:
     script: v2.2.0.issue-2856:2676:d23b7a2f45e8[MODIFIED], 2012/08/05 
15:38:28, by garyo on oberbrunner-dev
     engine: v2.2.0.issue-2856:2676:d23b7a2f45e8[MODIFIED], 2012/08/05 
15:38:28, by garyo on oberbrunner-dev
     engine path: ['/usr/local/lib/scons-2.2.0/SCons']
Copyright (c) 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 
2010, 2011, 2012 The SCons Foundation

My Python : 2.6.6 on Debian.

 >>> LOG
file 
/media/Sata_Data/JosDistroIndependentData/SoftwareUnderDevelopment/dlEmu8080/SConstruct,line 
220:
     Configure(confdir = .sconf_temp)
scons: Configure: Caught exception while building ".sconf_temp/conftest_0":

Traceback (most recent call last):
   File "/usr/local/lib/scons-2.2.0/SCons/Job.py", line 201, in start
     task.execute()
   File "/usr/local/lib/scons-2.2.0/SCons/SConf.py", line 352, in execute
     raise e
TypeError: can't write str to text stream
scons: Configure: no
 >>> END LOG


 >>> CODE
def dlCheckPKGConfig(Context,MinVersion):
   dlPkgConfig = Context.env['DL_CROSS'] + 'pkg-config'
   print dlBoldBlue + 'Checking for \'' + dlPkgConfig + '\' ... ' + 
dlNoAttrs
   Ret=Context.TryAction(
       dlPkgConfig + ' --atleast-pkgconfig-version=' + MinVersion)[0]
   Context.Result(Ret)
   print "FOOBAR :" + str(Ret)
   return Ret
 >>> END CODE

Called as in the wiki :

 >>> CODE
dlConf = Configure(dlDefaultEnv,
                    custom_tests = {'dlCheckPKGConfig' : dlCheckPKGConfig,
                                    'dlCheckPKG'       : dlCheckPKG })

if not dlConf.dlCheckPKGConfig('0.25'):
   dlPrintLog(dlLogFile,dlBoldRed,'pkg-config >= 0.25 not found.')
   dlPrintLog(dlLogFile,dlBoldRed,'Giving up.')
   Exit(1)
 >>> END CODE



-- 
Jos De Laender
www.jodela.be