ffmpeg-compat.eclass – Gentoo Development Guide

Name

ffmpeg-compat.eclass -- Helper functions to link with slotted ffmpeg-compat libraries

Description

To use this, run ffmpeg_compat_setup <slot> before packages use pkg-config, depend on media-video/ffmpeg-compat:<slot>, and ensure usage of both pkg-config --cflags and --libs (which adds -Wl,-rpath to find libraries at runtime). Always verify that it is linked with the right libraries after.

This eclass is intended as a quick-to-setup alternative to setting an upper bound on ffmpeg for packages broken with the latest version, and thus allow users to upgrade their normal ffmpeg.

This should still be a temporary measure, and it is recommended to keep migration bugs open rather than consider this eclass as being the "fix".

Unlike LLVM_SLOT-style, this does not have USE to select the slot and should instead pick only the highest one usable until package is fixed and can use non-slotted ffmpeg again.

Do not use both like || ( <ffmpeg-<ver> ffmpeg-compat:<slot> ), the package manager cannot know which version it linked against without USE flags. Unfortunately means a period where users may have two identical versions in stable before the newest major version is stabilized, but idea is to not mangle normal ffmpeg with slotting logic and make this an isolated temporary deal.

Supported EAPIs

8 9

Functions

ffmpeg_compat_add_flags

Append pkg-config --cflags libavcodec to CPPFLAGS and --libs-only-{L,other} to LDFLAGS for the current ABI.

Must run ffmpeg_compat_setup <slot> first.

Ideally this function should not be used, but can be useful when packages do not use pkg-config properly or drop some flags (common with cmake).

For multilib, ebuild should preserve previous flags by doing e.g. local -x CPPFLAGS=${CPPFLAGS} LDFLAGS=${LDFLAGS} first.

ffmpeg_compat_get_prefix <slot>

Return prefix of the installed ffmpeg-compat:<slot>. Binaries like ffmpeg will be found under <prefix>/bin if needed.

ffmpeg_compat_setup <slot>

Add ESYSROOT's ffmpeg-compat:<slot> to PKG_CONFIG_PATH for the current ABI.

Authors

Ionen Wolkens <ionen@gentoo.org>

Maintainers

Ionen Wolkens <ionen@gentoo.org>

Reporting Bugs

Please report bugs via https://bugs.gentoo.org/