The #pragma directive is a compiler specific instruction. There
are many things you can tell the compiler. For instance, the
#pragma pack n directive tells the compiler to override the /Zpn
command line argument and to use a new default structure packing
value. To see all of the possible #pragma directives, go to online
help, and index by #pragma directives, C/C++. You probably only
need to type in #pra and then click on C/C++ to get this far.