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 <- readLineStd
    -- read whatever user input in 3s, otherwise get Nothing
    b2 <- timeoutLowRes 30 $ withMVar stdinBuf readBuffer
    ...
    putStd "hello world!"

    -- Raw mode
    setStdinTTYMode UV_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

Output StdStream

Defined in Z.IO.StdStream

Methods

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

Input StdStream

Defined in Z.IO.StdStream

Methods

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

isStdStreamTTY :: StdStream -> Bool

getStdStreamFD :: StdStream -> IO FD

setStdinTTYMode :: TTYMode -> IO ()

Change terminal's mode if stdin is connected to a terminal.

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

Get terminal's output window size in (width, height) format, return (-1, -1) if stdout is a file.

stdin :: StdStream

The global stdin stream.

stdout :: StdStream

The global stdout stream.

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

stderr :: StdStream

The global stderr stream.

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

stdinBuf :: MVar (BufferedInput StdStream)

A global buffered stdin stream protected by MVar.

stdoutBuf :: MVar (BufferedOutput StdStream)

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 StdStream)

A global buffered stderr stream protected by MVar.

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

utils

printStd :: HasCallStack => ShowT a => a -> IO ()

Print a ShowT and flush to stdout.

readLineStd :: HasCallStack => IO Bytes

Read a line from stdin

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

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

Print a Builder and flush to stdout.

putLineStd :: 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 UV_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