| ZVON > References > Haskell reference |
| Intro / Search / ZVON |
| | Indexes | Syntax | Prelude | Ratio | Complex | Numeric | Ix | Array | List | Maybe | Char | Monad | >> IO << | Directory | System | Time | Locale | CPUTime | Random |
| Module: | IO |
|---|---|
| Function: | hGetPosn |
| Type: | Handle -> IO HandlePosn |
| Description: | Computation hGetPosn hdl returns the current I/O position of hdl as a value of the abstract type HandlePosn. If a call to hGetPosn h returns a position p, then computation hSetPosn p sets the position of h to the position it held at the time of the call to hGetPosn. Error reporting: the hSetPosn computation may fail with: isPermissionError if a system resource limit would be exceeded. |
| Related: | hSetPosn |
File: /tmp/foo.txt : Hello, world! Good bye!
Program source: import IO main = do hdl <- openFile "/tmp/foo.txt" ReadMode a <- hGetChar hdl pos <- hGetPosn hdl b <- hGetLine hdl print (a,b) c <- hGetChar hdl d <- hGetLine hdl print (c,d) hSetPosn pos e <- hGetChar hdl f <- hGetLine hdl print (e,f)
Output: ('H',"ello, world!")
Output: ('G',"ood bye!")
Output: ('e',"llo, world!")
|
|
|