RDEPEND

RDEPEND is a dependency classification used by the Gentoo Linux Portage package management system. It specifies the packages that must be present on a system for a given package to run correctly after installation. In other words, RDEPEND encodes the runtime requirements of the package.

It is distinct from DEPEND, which declares build-time dependencies necessary to compile or install the package, and from BDEPEND, which lists dependencies needed during the build process but not required at runtime. PDEPEND is another category used for conditional or alternative dependencies that may be satisfied by the package itself or by another package.

Portage uses RDEPEND to install and verify runtime availability. When a package is installed, Portage ensures that all packages listed in its RDEPEND are present. Removing or updating runtime dependencies can break the functioning of the installed package, so they are typically kept accurate and minimal. Maintainers may use USE flags to conditionally reduce or expand RDEPEND entries, depending on optional features.

Examples of RDEPEND entries include libraries the program links against, system services it relies on, or data files it needs at runtime (such as fonts or codecs).

Maintaining RDEPEND is part of ebuild maintenance; it should reflect actual runtime behavior and be updated when the package’s requirements change. Portage consults RDEPEND during dependency resolution to ensure a consistent runtime environment.