The Intel® C++ Compiler searches the default system areas for include files and whatever is specified by the I compiler option. The compiler searches directories for include files in the following order:
Directories specified by the I option
Directories specified in the environment variables
Default include directory
Use the X option to remove default directories from the include file search path.
For example, to direct the compiler to search the path /alt/include instead of the default path, do the following: