LibU is a multiplatform C library that comes under a BSD-style license. It includes many interdependent modules for accomplishing several tasks: memory allocation, networking and URI parsing, string manipulation, debugging, and logging in a very compact way, plus many other miscellaneous tasks. It has a small footprint (about 70KB for the default configuration), it is modular, and it has a multiplatform nature, making it an ideal candidate for embedded systems. KLone is an example of such usage.
Assimp is a portable and extensible library designed for reading various well-known 3D file formats. It provides APIs for C and C++ and several wrappers for other languages. It reads more than 20 different 3D file formats (including Collada, 3DS, OBJ, LWO, and X) into a straightforward, hierarchical in-memory data structure that can easily be read and processed by applications. Several post processing steps can be applied, such as normal and tangent computations, index buffer, and vertex cache optimization. The library supports complex multi-layer materials and skinned meshes with multiple animations. A Windows-based viewer utility is provided as an implementation reference.
lib4d_sql is a C library that provides the required functions (connect, prepare, execute, etc.) for writing an SQL client for 4D databases. It uses the public 4D SQL protocol, which is supported by 4D products since version 11. It is already used by the PDO_4D Open Source project, and it might be used to provide others drivers for JDBC, ADO, or ActiveRecord.
libposix is an impementation of the core functionality of all Unix systems. It is a full, cross-platform implementation of the POSIX 2008 standard. It is meant to replace existing implementations of a Unix system's core libraries. It is an exact implementation of POSIX 2008 and nothing else (no extensions, no previous POSIX versions). However, it works well with possible extensions to the core system functionallity (for example, GNU or BSD).
The fstrcmp library provides an fstrcmp function that returns a number between 0.0 (nothing alike) and 1.0 (identical); this can be used to suggest likely alternatives in error messages. Fuzzy comparisons for byte arrays, wide character strings, and multi-byte character strings are also available. In addition, there are integer alternatives for systems with slow floating point emulation.
The libcommon project is an API implementation in order to respond to general development needs for softwares written in C. This library gives to the developer some utility functions like advanced getopt management, an extra strings treatments function, debugging and tracing functions, and macros for generic lists support. Its goal is to avoid constant re-implementation of the same things for each new program. The libcommon API has been implemented in order to be multi-platform (compatible with i386, ia64, PPC, MIPS, and MIPS 64), hardened (high-level compilation restrictions and implementation requirements), and as few libc dependencies as possible.
hamsterdb Transactional Storage is an ANSI-C implementation of a key/value database engine. It has a lock-free architecture, thus supporting an arbitrary number of long-running transactions and resolves transaction conflicts in memory without accessing the disk. hamsterdb uses logical, idempotent logging for recovery. It is thread-safe and concurrent, moving performance intensive operations to the background. Every hamsterdb handle can be used from arbitrary threads.
libosl, the object storage layer, is a library for storing small to medium-sized data in relational tables. It is easy to use, lightweight, fast, and portable. libosl is suitable for applications that need only a small fraction of the features a full database management system provides.