If the file was unopened, succeeds vacuously. Otherwise closes the
file (by calling fclose),
throwing on error. Even if an exception is thrown, afterwards the File object is empty. This is different from detach in that it
always closes the file; consequently, all other File objects
referring to the same handle will see a closed file henceforth.
The D Programming Language's Unofficial Docs
beta
If the file was unopened, succeeds vacuously. Otherwise closes the file (by calling fclose), throwing on error. Even if an exception is thrown, afterwards the File object is empty. This is different from detach in that it always closes the file; consequently, all other File objects referring to the same handle will see a closed file henceforth.