LibraryCheck

Determine whether a shared library is available to be loaded by Raku

Synopsis

use LibraryCheck;

if !library-exists('sndfile', v1) {
    die "Cannot load libsndfile";
}

Description

This module provides a mechanism that will determine whether a named shared library is available and can be used by NativeCall.

It exports a single function library-exists that returns a boolean to indicate whether the named shared library can be loaded and used. The library name should be supplied without any (OS-dependent) "lib" prefix and no extension (for example, 'crypt' for libcrypt.so).

This can be used in a builder to determine whether a module has a chance of working (and possibly aborting the build), or in tests to cause the tests that may rely on a missing library to be skipped.

The second positional argument is a Version object that indicates the version of the library that is required, it defaults to v1, if you don't care which version exists then it possible to pass a new Version object without any version parts (i.e., Version.new()). Many systems require that the version is specified, so if portability is a concern, an actual version number should be given.

If the :exception adverb is passed to library-exists then an exception (X::NoLibrary) will be thrown if the library isn't available rather than returning False. So the case above can be more simply written as:

library-check('sndfile', v1, :exception);

The implementation is somewhat of a hack currently and definitely shouldn't be taken as an example of nice Raku code.

Installation

Assuming you have a working Rakudo installation you should be able to install this with zef:

# From the source directory

zef install .

# Remote installation

zef install LibraryCheck

Other install mechanisms may be become available in the future.

Support

Suggestions/patches are welcomed via github at https://github.com/jonathanstowe/LibraryCheck/issues

I'd be particularly interested in having it work properly on all the platforms that rakudo will work on.

Licence

Please see the LICENCE file in the distribution.

© Jonathan Stowe 2015 - 2021