Haskell IO and closing files

Question

When I open a file for reading in Haskell, I\'ve found that I can\'t use the contents of the file after closing it. For example, this program will print the contents of a file:<

Answer 1

The explanation is rather long to be included here. Forgive me for dispensing a short tip only: you need to read about "semi-closed file handles" and "unsafePerformIO".

In short - this behaviour is a design compromise between a semantic clearness and lazy evaluation. You should either postpone hClose until you are absolutely sure you woudnt be doing anything with the file content (like, call it in error handler, or somesuch), or use something else besides hGetContents to get file contents non-lazily.