Z.IO.StdStream

This module provides stdin/stderr/stdout reading and writings. Usually you don't have to use stderr or stderrBuf directly, Logger provides more logging utilities through stderr. While stdinBuf and stdoutBuf is useful when you write interactive programs, Buffered module provide many reading and writing operations. Example:

import Control.Concurrent.MVar
import Z.IO.LowResTimer
import Z.IO.Buffered
import Z.IO.StdStream
import qualified Z.Data.Vector as V
import qualified Z.Data.Builder as B
main = do
    -- read by 'n'
    b1 <- readStd
    -- read whatever user input in 3s, otherwise get Nothing
    b2 <- timeoutLowRes 30 $ withMVar stdinBuf readBuffer
    ...
    putStd "hello world!"

    -- Raw mode
    setStdinTTYMode TTY_MODE_RAW
    forever $ do
        withMVar stdinBuf $  i -> withMVar stdoutBuf $  o -> do
            bs <- readBuffer i
            let Just key = V.headMaybe bs
            writeBuilder o (B.hex key)
            flushBuffer o

Standard input & output streams

data StdStream

Standard input and output streams

We support both regular file and TTY based streams, when initialized uv_guess_handle is called to decide which type of devices are connected to standard streams.

Note StdStream is not thread safe, you shouldn't use them without lock. For the same reason you shouldn't use stderr directly, use Logger module instead.

Instances

Print StdStream

Defined in Z.IO.StdStream

Methods

toUTF8BuilderP :: Int -> StdStream -> Builder ()

Input StdStream

Defined in Z.IO.StdStream

Methods

readInput :: StdStream -> Ptr Word8 -> Int -> IO Int

Output StdStream

Defined in Z.IO.StdStream

Methods

writeOutput :: StdStream -> Ptr Word8 -> Int -> IO ()

Show StdStream

Defined in Z.IO.StdStream

Methods

showsPrec :: Int -> StdStream -> ShowS

show :: StdStream -> String

showList :: [StdStream] -> ShowS

getStdStreamFD :: StdStream -> IO FD

Get the standard stream's OS file descriptor.

isStdStreamTTY :: StdStream -> Bool

Is this standard stream connected to a TTY device?

setStdinTTYMode :: TTYMode -> IO ()

Change terminal's mode if stdin is connected to a terminal, do nothing if stdout is not connected to TTY.

withRawStdin :: IO a -> IO a

Set stdin to raw mode before run IO, set back to normal after.

getStdoutWinSize :: HasCallStack => IO (Int, Int)

Get terminal's output window size in (width, height) format, return (-1, -1) if stdout is not connected to TTY.

stdin :: StdStream

The global stdin stream.

stdout :: StdStream

The global stdout stream.

If you want a buffered device, consider use the stdoutBuf first. If you want to write logs, don't use stdout directly, use Logger instead.

stderr :: StdStream

The global stderr stream.

If you want a buffered device, consider use the stderrBuf first. | If you want to write logs, don't use stderr directly, use Logger instead.

stdinBuf :: MVar BufferedInput

A global buffered stdin stream protected by MVar.

If you want a buffered device, consider use the stdinBuf first.

stdoutBuf :: MVar BufferedOutput

A global buffered stdout stream protected by MVar.

If you want to write logs, don't use stdoutBuf directly, use Logger instead.

stderrBuf :: MVar BufferedOutput

A global buffered stderr stream protected by MVar.

If you want to write logs, don't use stderrBuf directly, use Logger instead.

utils

readStd :: HasCallStack => IO Bytes

Read a line from stdin(in normal mode).

This function will throw ECLOSED when meet EOF, which may cause trouble if stdin is connected to a file, use readLine instead.

printStd :: (HasCallStack, Print a) => a -> IO ()

Print a Print and flush to stdout, without linefeed.

putStd :: HasCallStack => Builder a -> IO ()

Print a Builder and flush to stdout, without linefeed.

printStdLn :: (HasCallStack, Print a) => a -> IO ()

Print a Print and flush to stdout, with a linefeed.

printStdLnP :: (HasCallStack, Print a) => a -> Parser ()

Similar to printStdLn, Parser debug tool.

putStdLn :: HasCallStack => Builder a -> IO ()

Print a Builder and flush to stdout, with a linefeed.

re-export

withMVar :: MVar a -> (a -> IO b) -> IO b

withMVar is an exception-safe wrapper for operating on the contents of an MVar. This operation is exception-safe: it will replace the original contents of the MVar if an exception is raised (see Control.Exception). However, it is only atomic if there are no other producers for this MVar.

Constant

TTYMode

type TTYMode = CInt

Terminal mode.

When in TTY_MODE_RAW mode, input is always available character-by-character, not including modifiers. Additionally, all special processing of characters by the terminal is disabled, including echoing input characters. Note that CTRL+C will no longer cause a SIGINT when in this mode.

pattern TTY_MODE_NORMAL :: TTYMode

pattern TTY_MODE_RAW :: TTYMode