Cross Platform Perl Development IDE.Current Alpha is for WIN32 written in Delphi. Initial Plan is too rewrite the IDE in Perl itself.
This recipe provides a couple of cross-platform utility functions, 'open' and 'mailto', for opening files and URLs in the registered default application and for sending e-mails using the user's preferred composer.
The python standard library...
Header-only cross platform libraries
Casm is a cross platform assembler for X86, MIPS, PowerPC and SPARC. It is designed for use with JIT compiling.
A cross-platform, cross-compiler, cross-CPU C header library for programming with SIMD instruction sets. X86 (MMX/SSE/SSE2) GCC and MSVC, PPC Altivec GCC, WMMX ARM GCC, and software emulated SIMD are supported.
A library for the creation of cross-platform, GUI-independant wizards. Supports extensible front-ends, currently implementing HTTP and KDE, as well as extensible input types.
A C++ based framework for highly object-oriented cross-platform programming. Includes Thread, Processes,Filesystem access,GUI, etc. plus a set of generic utilities like Strings,Data structures,advanced debugging tools, etc.
Cross-Platform System Library is a portable C++ run-time library that provides support for manipulating system resources, such as thread, process, mutex, and synchronize, in Win32 and POSIX(UNIX, Linux, Mac OS X) platforms.
Classes, modules and sample applications from REALbasic Cross-Platform Application Development, written by Mark S. Choate.
SimpleSockets is a cross platform library written in C++ with support for Windows, Linux, and Unix. Features include blocking/non-blocking sockets, polling, thread safe, and signal safe.