An RSP file contains one or more command line arguments used by the C# compiler (CSC) included with the .NET Compiler Platform (also known as Roslyn). It may store one or more compiler options and the names of one or more source code files to be compiled. RSP files are saved in plain text format and are processed by the CSC with every compilation.

The RSP file allows you to list compiler options and source code files to be processed by CSC as if you specified them on the command line. If the RSP file only stores one compiler option specification then it should be restricted to one line. Multiple compiler options and source code files may appear on multiple lines or one line. # is used for comments in an RSP file and @ is used to specify multiple RSP files in a compilation. For example @sample.rsp @sample2.rsp @sample3.rsp specifies the sample.rsp, sample2.rsp, and sample3.rsp files to be compiled. NOTE: The csc.rps file is deployed with CSC (csc.exe file) and references all the assemblies shipped with the .NET framework. The csc.rps file will not be processed by the CSC if the -nopconfig option is specified.