cysignals: interrupt and signal handling for Cython

Cython and interrupts

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.

Requirements

• Python >= 3.6
• Cython >= 0.28
• Sphinx >= 1.6 (for building the documentation)
• PARI/GP (optional; for interfacing with the PARI/GP signal handler)

Links

• 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/

Changelog

1.11.0 (unreleased)

• Fixed compilation with glib 3.34.

1.10.3 (2021-03-16)

• Improved installation of cysignals with pip install -e. [#130]
• Fixed compilation of OpenMP modules that also use cysignals. [#128]
• Fixed segmentation fault that could occur when sig_occurred() is called recursively during garbage collection. [#127]
• Improved error reporting of signals that occurred inside sig_on() as opposed to outside them.
• Fixed bug in the cysignals_example package. [#113]

For changes in previous releases, see the best source available is to compare git tags: https://github.com/sagemath/cysignals/tags