/syntax_check switch
The /syntax_check switch indicates that the compiler checks only syntax and does not generate output files.
midl /syntax_check
midl /Zs
This switch has no parameters.
This switch overrides all other switches that specify information about output files.
You can also specify syntax-checking mode with the MIDL compiler option /Zs.
midl /Zs filename.idl
midl /syntax_check filename.idl