| ZVON > References > Haskell reference |
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| Module: | IO |
|---|---|
| Function: | hSeek |
| Type: | Handle -> SeekMode -> Integer -> IO () |
| Description: |
Computation hSeek hdl mode i sets the position of handle hdl depending on mode. If mode is:
* AbsoluteSeek: the position of hdl is
set to i.
* RelativeSeek: the position of hdl is
set to offset i from the current position.
* SeekFromEnd: the position of hdl is set
to offset i from the end of the file.
The offset is given in terms of 8-bit bytes. Error reporting: the hSeek computation may fail with: isPermissionError if a system resource limit would be exceeded. |
| Related: |
File: /tmp/foo.txt : Hello, world! Good bye!
Program source: import IO main = do hdl <- openFile "/tmp/foo.txt" ReadMode a <- hGetChar hdl hSeek hdl AbsoluteSeek 4 b <- hGetChar hdl print (a,b) c <- hGetChar hdl hSeek hdl RelativeSeek 3 d <- hGetChar hdl print (c,d) e <- hGetChar hdl hSeek hdl SeekFromEnd (-3) f <- hGetChar hdl print (e,f)
Output: ('H','o')
Output: (',','r')
Output: ('l','y')
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