Bindings for low level C library I/O routines

Version 4.5.1
Released 2018-01-10

This project is maintained by Max Horn

README file for the IO GAP4 package

To get the newest version of this GAP 4 package download the archive file


and unpack it using

gunzip io-x.x.tar.gz; tar xvf io-x.x.tar

Do this in a directory called pkg, preferably (but not necessarily) in the pkg subdirectory of your GAP 4 installation. It creates a subdirectory called io.

To install this package do

cd io

If you installed io in another directory than the usual pkg subdirectory, do

./configure --with-gaproot=path

where path is a path to the main GAP root directory. See

./configure --help

for further options.

Afterwards call make to compile a binary file.

The package willnot work without this step.

If you installed the package in another pkg directory than the standard pkg directory in your GAP 4 installation, then you have to add the path to the directory containing your pkg directory to GAP’s list of directories. This can be done by starting GAP with the -l command line option followed by the name of the directory and a semicolon. Then your directory is prepended to the list of directories searched. Otherwise the package is not found by GAP. Of course, you can add this option to your GAP startup script.

If you installed GAP on several architectures, you must execute the configure/make step for each of the architectures. You can either do this immediately after configuring and compiling GAP itself on this architecture, or alternatively (when using version 4.5 of GAP or newer) set the environment variable “CONFIGNAME” to the name of the configuration you used when compiling GAP before running “./configure”. Note however that your compiler choice and flags (environment variables “CC” and “CFLAGS” need to be chosen to match the setup of the original GAP compilation. For example you have to specify 32-bit or 64-bit mode correctly!

Recompiling the documentation is possible by the command gap makedoc.g in the IO directory. But this should not be necessary.

For bug reports, feature requests and suggestions, please refer to