PyQt/MiniSipExample

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SIP: Generate Bindings for a class derived from Qt

This example shows how to use SIP for generating bindings to Qt c++ modules. The Example shown in the sip-documentation is not complete and perhaps we can prevent you to waste hours of time to get things run.

Before You Begin

1. Install Qt4

2. Build and install SIP

3. Build and install PyQt

Qt Fragment

We define a silly class derived from QString.\

hello.h:

#ifndef _HELLO_H_
#define _HELLO_H_
#include <QString>
class Hello : public QString {
  public:
    Hello();
};
#endif

hellp.cpp:

#include "hello.h"

Hello::Hello() {
  append("Hello World");
}

hello.pro

TEMPLATE = lib

CONFIG   += qt warn_on release

HEADERS  = hello.h
SOURCES  = hello.cpp
TARGET   = hello

DESTDIR  = /usr/lib

Now We call qmake for qt4 to generate the makefile, then make to build the example and install it. DESTDIR describes the directory in which the executable or binary file will be placed. DESTDIR ist Platform depended.

$ qmake{.backtick}
$ sudo make{.backtick}

Telling SIP what to do

We need two files.\

hello.sip:

%Module hello 0

%Import QtCore/QtCoremod.sip

class Hello : QString
{
%TypeHeaderCode
#include "../c++/hello.h"
%End

public:
  Hello();
};

configure.py:

   1 import os
   2 import sipconfig
   3 from PyQt4 import pyqtconfig
   4 
   5 # The name of the SIP build file generated by SIP and used by the build
   6 # system.
   7 build_file = "hello.sbf"
   8 
   9 # Get the PyQt configuration information.
  10 config = pyqtconfig.Configuration()
  11 
  12 # Get the extra SIP flags needed by the imported qt module.  Note that
  13 # this normally only includes those flags (-x and -t) that relate to SIP's
  14 # versioning system.
  15 qt_sip_flags = config.pyqt_sip_flags
  16 
  17 # Run SIP to generate the code.  Note that we tell SIP where to find the qt
  18 # module's specification files using the -I flag.
  19 os.system(" ".join([config.sip_bin, "-c", ".", "-b", build_file, "-I", 
  20 config.pyqt_sip_dir, qt_sip_flags, "hello.sip"]))
  21 
  22 # We are going to install the SIP specification file for this module and
  23 # its configuration module.
  24 installs = []
  25 
  26 installs.append(["hello.sip", os.path.join(config.default_sip_dir, 
  27 "hello")])
  28 
  29 # Create the Makefile.  The QtModuleMakefile class provided by the
  30 # pyqtconfig module takes care of all the extra preprocessor, compiler and
  31 # linker flags needed by the Qt library.
  32 makefile = pyqtconfig.QtCoreModuleMakefile(
  33      configuration=config,
  34          build_file=build_file,
  35          installs=installs
  36      )
  37 
  38 # Add the library we are wrapping.  The name doesn't include any platform
  39 # specific prefixes or extensions (e.g. the "lib" prefix on UNIX, or the
  40 # ".dll" extension on Windows).
  41 makefile.LFLAGS.append("-L../c++")
  42 makefile.extra_libs = ["hello"]
  43 
  44 # Generate the Makefile itself.
  45 makefile.generate()

We build the Python-Modul and install it

$ python configure.py{.backtick}
$ make{.backtick}
$ sudo make install{.backtick}

Simple Python Example

Now you can use the class inside the python interpreter:

   1 import hello
   2 
   3 a=hello.Hello()
   4 print a