Setting Compiler Options
C and C++ compiler options can be set either in the development environment or on the command line.
You can set compiler options for each project in its Property Pages dialog box. In the left pane, select Configuration Properties, C/C++ and then choose the compiler option category. The topic for each compiler option describes how it can be set and where it is found in the development environment. See Compiler Options for a complete list.
You can set compiler (CL.exe) options:
Options specified in the CL environment variable are used every time you invoke CL. If a command file is named in the CL environment variable or on the command line, the options specified in the command file are used. Unlike either the command line or the CL environment variable, a command file allows you to use multiple lines of options and filenames.
Compiler options are processed "left to right," and when a conflict is detected, the last (rightmost) option wins. The CL environment variable is processed before the command line, so in any conflicts between CL and the command line, the command line takes precedence.