FWDSTAMP adds entry points, called forwarders, to a dynamic link library file (.DLL). Forwarders point to API functions or other exported code or data. They contain an import reference so that the final target address of the forwarded entry is contained in a different module. A forwarder might be called an imported export.
When a file has a fix-up to a forwarded entry point, the loader resolves that fix-up to the address of the entry point that the forwarder imports, by traversing the chain of forwarders until the end of the chain (a nonforwarded export) is reached. All forwarders are implicitly exported.
The imported entry point that a forwarder refers to may itself be another forwarder. The loader will process a chain of forwarders until a nonforwarder entry point is encountered.
There is no run-time cost to forwarders; however, there is a slight load-time cost as the loader resolves forwarder chains with their final addresses.