Command-Line Warning D9027

source file '<filename>' ignored

CL.exe ignored the input source file.

This warning can be caused by a space between the /Fo option and an output filename on a command line with the /c option. For example:

cl /c /Fo output.obj input.c 

Because there is a space between /Fo and output.obj, CL.exe takes output.obj as the name of the input file. To fix the problem, remove the space:

cl /c /Fooutput.obj input.c