What is the use of 'pragma' in C language?

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.