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author | Richard Jones <rjones@redhat.com> | 2010-09-02 10:58:28 +0100 |
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committer | Richard Jones <rjones@redhat.com> | 2010-09-08 16:33:12 +0100 |
commit | 1fa68d080a66a70ec4879e2e6b5e5b8acb36b542 (patch) | |
tree | 6f425d903bf48028667f047ba3c7a3025184698e | |
parent | 32d357bb907441e2a446a4e359a698a5c9d6c916 (diff) | |
download | libguestfs-1fa68d080a66a70ec4879e2e6b5e5b8acb36b542.tar.gz libguestfs-1fa68d080a66a70ec4879e2e6b5e5b8acb36b542.tar.xz libguestfs-1fa68d080a66a70ec4879e2e6b5e5b8acb36b542.zip |
perl: Add documentation about testing availability of methods and features.
(cherry picked from commit 0f24424f357e854a9da382de11e4fe81305c8743)
-rwxr-xr-x | src/generator.ml | 31 |
1 files changed, 31 insertions, 0 deletions
diff --git a/src/generator.ml b/src/generator.ml index b31b3c9f..b61e43c5 100755 --- a/src/generator.ml +++ b/src/generator.ml @@ -9251,6 +9251,37 @@ when the final reference is cleaned up is OK). =back +=head1 AVAILABILITY + +From time to time we add new libguestfs APIs. Also some libguestfs +APIs won't be available in all builds of libguestfs (the Fedora +build is full-featured, but other builds may disable features). +How do you test whether the APIs that your Perl program needs are +available in the version of C<Sys::Guestfs> that you are using? + +To test if a particular function is available in the C<Sys::Guestfs> +class, use the ordinary Perl UNIVERSAL method C<can(METHOD)> +(see L<perlobj(1)>). For example: + + use Sys::Guestfs; + if (defined (Sys::Guestfs->can (\"set_verbose\"))) { + print \"\\$h->set_verbose is available\\n\"; + } + +To test if particular features are supported by the current +build, use the L</available> method like the example below. Note +that the appliance must be launched first. + + $h->available ( [\"augeas\"] ); + +Since the L</available> method croaks if the feature is not supported, +you might also want to wrap this in an eval and return a boolean. +In fact this has already been done for you: use +L<Sys::Guestfs::Lib(3)/feature_available>. + +For further discussion on this topic, refer to +L<guestfs(3)/AVAILABILITY>. + =head1 COPYRIGHT Copyright (C) %s Red Hat Inc. |