Software programs are often made to run on systems that are completely different from the system in which the program is coded or developed. This process of adapting software across systems is known as porting.
ref:
Porting C++ Code from Windows to Unix -
Porting from Unix to Windows -
Porting Applications to 64bit OS -
Tru64 porting Guide - http://h30097.www3.hp.com/docs/pub_page/porting.html
Sun Solaris to Compaq Tru64 UNIX Porting Guide - http://www.tru64unix.compaq.com/docs/porting/HTML/solaris.html
Porting Unix/Linux Applications to Mac OS - http://www.krsaborio.net/apple/research/acrobat/0206.pdf
Developing and Porting C and C++ Applications on AIX - http://www.redbooks.ibm.com/redbooks/pdfs/sg245674.pdf
Porting Unix Applications to AS/400 - http://www.common.be/pdffiles/F00p03Common.pdf
Porting IRIX Applications to Tru64 - http://h30097.www3.hp.com/docs/porting/IRIX.pdf
Android NDK(Develop native apps on Android) -