Free client library software for linux

GPM client library (libgpm) package is an stand-alone version of GPMs client library, used by many console applications for mouse access.
Despite the (now quite aged) GPM package it contains just the client part (no server), and provides a pkgconfig descriptor (libgpm.pc) for easy importing.
Enhancements:
- This release pulls in some outstanding patches from upstream and Gentoo. It adds a Gentoo ebuild file.

XML-RPC Client/Server C Library is a cross-platform software written in C that supports persistent HTTP/1.1 conenctions over SSL and comes with XML-RPC interface description language and client/server code compiler. Libxr depends on glib2 and libxml2.
Main features:
- Persistent connections over HTTP/1.1
- SSLv3/TLSv1 using OpenSSL.
- XML-RPC interface description language (XDL).
- XML-RPC client stubs/servlet skels compiler.
- Multiple servlets per server.
- Servlet lifetime (init -- call -- call -- fini).
- Multiplatform (linux, mingw32 on windows).
- IPV6 as soon as OpenSSL 0.9.9 is released.

Ssh library was designed to be used by programmers needing a working SSH implementation by the mean of a library. Runs only on x86 linux, bsd and MacOS X.
libssh is a C library to access SSH 2 services from a program. It can remotely execute programs, transfer files, and serve as a secure and transparent tunnel for remote programs. Its Secure FTP implementation can play with remote files easily, without third-party programs others than libcrypto (from OpenSSL).
Main features:
- Full C library functions for manipulating a client-side SSH connection
- Lesser GPL licensing -SSH2 protocol compliant
- Fully configurable sessions
- Support for AES-128,AES-192,AES-256,blowfish, in cbc mode
- Use multiple SSH connections in a same process, at same time
- Use multiple channels in the same connection
- Thread safety when using different sessions at same time
- Basic but correct SFTP implementation (secure file transfer)
- RSA and DSS server public key supported
- Compression support (with zlib)
- Public key (RSA and DSS), password and keyboard-interactive authentication
- A complete documentation about its API
- Runs and tested under amd64, x86, arm, sparc32, ppc under Linux, Bsd, MacosX and Solaris
- A developer listening to you
Enhancements:
- Connection timeout support
- Keyboard-interactive authentication (used by Pam with SSH)
- Server public keys management
- 64 bits cpu support
- Enhanced documentation
- and of course a huge number of bugfixe

STUN Protocol Library provides the Simple Traversal of UDP through NATs Library.
STUN Protocol Library, Client and Server implements a simple STUN (Simple Traversal of UDP through NATs) server and client, using the included library.
The STUN protocol is described in the IETF RFC 3489, available from the IETF.
STUN is a lightweight protocol that allows applications to discover the presence and types of Network Address Translators (NATs) and firewalls between them and the public Internet.
It also provides the ability for applications to determine the public IP addresses allocated to them by the NAT.
STUN works with nearly all existing NATs, and does not require any special behavior from them.
As a result, it allows a wide variety of applications to work through existing NAT infrastructure.
The STUN protocol is very simple, being almost identical to echo.
Enhancements:
- Changed to new terminology.

libapreq is a shared library with associated modules for manipulating client request data via the Apache API.
Generic Apache Request Library also includes language bindings for Perl (Apache::Request and Apache::Cookie). Functionality includes:
parsing of application/x-www-form-urlencoded data
parsing of multipart/form-data
parsing of HTTP cookies
Enhancements:
- This release adds some Perl/C API fixes and build improvements.

ZRTP Protocol Library is an implementation of Phil Zimmermanns ZRTP protocol, created based on and interoperable with Zfone beta 2.

Using this package, together with GNU ccrtp (1.5.0 or later) provides a zrtp implimentation that can be directly embedded into client and server applications, rather than the overhead penalty of using an external proxy such as zphone. The first application to demonstrate this capability is the 0.8.2 release of the Twinkle softphone client.

Please note, this library is licensed under the GNU GPL, version 2 or later, and has been copyright assigned to the Free Software Foundation.

The Ionflux Tools Class Library is a lightweight multi-platform C++ framework designed for rapid development of applications in a client/server architecture.
The Ionflux Tools Class Library is released under the GNU General Public License, meaning it is free software! (See LICENSE in the distribution for more information.)
Main features:
- Memory management (object pools, reference counting, parent objects).
- Logging/console output facility.
- Command line parsing.
- Configuration file I/O.
- Database interface.
- IO multiplexing.
- Generic, serializable tree data structure.
- Perl-compatible regular expression pattern matching.
- String Filters.
- Template Engine, including Class templates.
- Advanced date and time handling (not restricted to the POSIX epoch, supporting time zone conversions).
- Generic byte string tokenizer.
- TCP socket API.
- Generic TCP client and server, message based client and server, and authenticated client and server.
- Support for the Cairo vector graphics API (http://www.cairographics.org/).
- Miscellaneous helpful and easy to use utility functions.