test.cin the LispWorks Editor. Note that the buffer is in C Mode, indicated by "(C)" in the mode line.
Buffer > Compile, or equivalently run
Meta+X Compile Buffer.
lw:compile-systemwould use, and the object file is loaded. The object file name is printed in the Output tab. It is written in your temporary directory (usually that given by the value of the environment variable
TEMP) and deleted after register-module is called on it.
LispWorks Foreign Language Interface User Guide and Reference Manual - 7 Dec 2011