Monthly Archives: October 2011

IPython Qt Console and printf

The recent 0.11 release of IPython includes a Qt-based console which offers an improved experience compared to running IPython in a terminal. In particular, the console feels like a terminal but offers multi-line editing, syntax highlighting, graphical tooltips, and inline plot figures.

But when I tried to run an existing script in the new IPython Qt Console, the usual overly verbose set of diagnostic messages did not appear! The symtoms were:

  • Regular print statements in Python worked fine.
  • printf statements in C-code wrapped with Boost.Python did not appear.

Read on to see a solution. Continue reading

FILE* and Boost.Python

One great feature of Boost.Python is the ability to write custom converters from Python types to C++ arguments. Most Boost.Python documentation, including the incredibly helpful post by misspent, show you how to write “rvalue” converters (e.g., pass-by-value or pass-by-const-reference).

However if you need to wrap a function which takes a FILE* argument the previous approach will not prove fruitful. But Boost.Python is clearly capable of handling a similar situation, namely the implicit conversion from a Python string type to a char* type. Since the conversion from the internal PyObject* to char* is likely to be done with the PyString_AsString function, I went off in search of that code.

Continue reading