[PyQt] Platforms directive or tags, or both?

Jens Thoms Toerring jt at toerring.de
Thu Oct 18 17:49:20 BST 2012


On Thu, Oct 18, 2012 at 09:42:30AM -0600, Larry Shaffer wrote:
> I'm working on a fix for Mac (for QGIS project) where size_t needs a
> different typedef in a sip file than other platforms.
> See: http://hub.qgis.org/issues/6505
> The build system is CMake that passes -t WS_MACX from the found PyQt4
> config on the command line. So, I wrote a simple:
> %If (WS_MACX)
> typedef unsigned long size_t;
> %End
> %If (!WS_MACX)
> typedef unsigned int size_t;
> %End

Since what size_t is is rather platform dependend I'd suggest
to use a different way that determines its type in the process
of making the SIP project. For this I have the following func-
tion defined in my 'configure.py'  script


def create_size_t_sip( configuration ) :
    Creates and runs a program that writes out a file named 'size_t.sip',
    containing the correct typedefs for size_t and ssize_t for the system
    we're going to built the wrapper library on.

    name = 'size_t_check.cpp';

    if os.path.exists( './size_t.sip' ) :

    open( name, 'w' ).write(
'''#include <cstdlib>
#include <fstream>
#include <typeinfo>
using namespace std;
int main( ) {
    ofstream f;
    f.open( "size_t.sip", ios::out );
    if ( ! f.is_open( ) )
        return EXIT_FAILURE;

    if ( typeid( size_t ) == typeid( unsigned int ) )
        f << "typedef unsigned int size_t;\\n"
          << "typedef int ssize_t;\\n";
    else if ( typeid( size_t ) == typeid( unsigned long int ) )
        f << "typedef unsigned long size_t;\\n"
          << "typedef long ssize_t;\\n";
        f << "typedef unsigned long long size_t;\\n"
          << "typedef long long ssize_t;\\n";

    f.close( );
    return 0;
''' )

    makefile = pyqtconfig.sipconfig.ProgramMakefile( configuration,
                                                     console = True )

    # This flag doesn't seem to be set in the Windows build of python, but
    # it's necessary for the (Windows) library to allow use of exceptions

    if sys.platform == 'win32' :
        makefile.extra_cxxflags.append ( '/EHsc' )

    exe, build = makefile.build_command( name )

    # On Unix we may need './' before the name of the executable while
    # on Windows with Visual Studio 2008 the program doesn't get run when
    # the '/MD' option (which is for DLLs) is used (we can't be sure if
    # the option is given as '-MD' or as '/MD' so check for both).

    if sys.platform != 'win32' :
        exe = './' + exe
    else :
        build = build.replace( '-MD', '' )
        build = build.replace( '/MD', '' )

    if os.system( build ) != 0 :
        print "Failed to create program for creating size_t.sip"
        exit( )

    os.remove( name )

    if os.system( exe ) != 0 :
        print 'Failed to run program for creating size_t.sip'
        os.remove( exe )
        exit( )

    os.remove( exe )


This is supposed to write out a small (C++) test program, com-
pile and then run it, writing out a file named 'size_t.sip'
with the correct definition of size_t (and also 'ssize_t').
This 'size_t.sip' file should be made part of the list of SIP
files you that make up your project. The abouve function would
be called in 'configure,py' rather early, possibly like this

config = pyqtconfig.Configuration( )
create_size_t_sip( config )

I only have tested this with Linux and Windows (with V2008),
some tweaks may be necessary for the Mac platform which I
don't have access to,
                            Best regards, Jens
  \   Jens Thoms Toerring  ________      jt at toerring.de
   \_______________________________      http://toerring.de

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