When writing Cython code, special care must be taken to ensure that the code can be interrupted with CTRL-C. Since Cython optimizes for speed, Cython normally does not check for interrupts. For example, code like the following cannot be interrupted in Cython:

while True:
    pass

The cysignals package provides mechanisms to handle interrupts (and other signals and errors) in Cython code.

• Python 2.7 or Python >= 3.4
• Cython >= 0.28
• Sphinx >= 1.6 (for building the documentation)
• PARI/GP (optional; for interfacing with the PARI/GP signal handler)

• cysignals on the Python package index: https://pypi.org/project/cysignals/
• cysignals code repository and issue tracker on GitHub: https://github.com/sagemath/cysignals
• full cysignals documentation on Read the Docs: http://cysignals.readthedocs.io/