some package:base-prelude

One or more.
Superclass for asynchronous exceptions.
The SomeException type is the root of the exception type hierarchy. When an exception of type e is thrown, behind the scenes it is encapsulated in a SomeException.
hGetBufSome hdl buf count reads data from the handle hdl into the buffer buf. If there is any data available to read, then hGetBufSome returns it immediately; it only blocks if there is no data to be read. It returns the number of bytes actually read. This may be zero if EOF was reached before any data was read (or if count is zero). hGetBufSome never raises an EOF exception, instead it returns a value smaller than count. If the handle is a pipe or socket, and the writing end is closed, hGetBufSome will behave as if EOF was reached. hGetBufSome ignores the prevailing TextEncoding and NewlineMode on the Handle, and reads bytes directly.