-ext

Specifies which file name extension to apply to object files.

  -ext extension
  
  

extension

The extension to apply to object files. Use these rules to specify the extension:

• Limited to a maximum length of 14 characters
• Extensions specified without a leading period replace the source file's extension. For example, if extension is " o" (without quotes), then source.cpp becomes source.o.
• Extensions specified with a leading period ( .extension) are appended to the object files name. For example, if extension is " .o" (without quotes), then source.cpp becomes source.cpp.o.

This command is global. The default setting is .o.