Was this page helpful?
Your feedback about this content is important. Let us know what you think.
Additional feedback?
1500 characters remaining
Export (0) Print
Expand All
Important This document may not represent best practices for current development, links to downloads and other resources may no longer be valid. Current recommended version can be found here.

Module-Definition (.def) Files

Module-definition (.def) files provide the linker with information about exports, attributes, and other information about the program to be linked. A .def file is most useful when building a DLL. Because there are linker options that can be used instead of module-definition statements, .def files are generally not necessary. You can also use __declspec(dllexport) as a way to specify exported functions.

You can invoke a .def file during the linker phase with the /DEF (Specify Module-Definition File) linker option.

If you are building an .exe file that has no exports, using a .def file will make your output file larger and slower loading.

See the following sections for more information:

Community Additions

ADD
Show:
© 2015 Microsoft