Programbibliotek

Programbibliotek, commonly known as a software library, is a collection of prewritten routines, data structures, and other resources that programs can reuse to perform common tasks. Libraries encapsulate functionality behind a defined interface, allowing developers to leverage existing code and focus on higher-level design. They are distributed separately from executables and are linked into an application during the build process or, in some cases, at runtime.

Two main forms exist: static and dynamic libraries. Static libraries are incorporated into the final executable at compile time, while dynamic (shared) libraries exist as separate files and are loaded by the program when needed. Static libraries may have extensions such as .a or .lib, whereas dynamic libraries use .so on Unix-like systems, .dll on Windows, and .dylib on macOS. Dynamic linking enables multiple programs to share a single library instance in memory and allows updating libraries without recompiling dependents.

Libraries expose APIs documented for use by developers. The stability and compatibility of these interfaces are important, as programs rely on specific versions. Languages often provide language-specific packaging, headers, and, for cross-language use, bindings or wrappers that adapt a library’s API to a target language.

Distribution and management involve package repositories and dependency management systems. Versioning schemes (e.g., semantic versioning) communicate compatibility, while licensing, provenance, and security advisories require ongoing attention to maintain safe and legal use of libraries.

In practice, programbibliotek underpin both standard language libraries and extensive ecosystems of third-party components, enabling faster development, code reuse, and modular design, while posing challenges in dependency management and risk assessment.