OpenEuphoria

8.8 Pipe Input/Output

8.8.1 Notes

Due to a bug, Euphoria does not handle STDERR properly STDERR cannot captured for Euphoria programs (other programs will work fully) The IO functions currently work with file handles, a future version might wrap them in streams so that they can be used directly alongside other file/socket/other-streams with a stream_select() function.

8.8.2 Accessor Constants

8.8.2.1 STDIN

include std/pipeio.e
namespace pipeio
public enum STDIN

Child processes standard input

8.8.2.2 STDOUT

include std/pipeio.e
namespace pipeio
public enum STDOUT

Child processes standard output

8.8.2.3 STDERR

include std/pipeio.e
namespace pipeio
public enum STDERR

Child processes standard error

8.8.2.4 PID

include std/pipeio.e
namespace pipeio
public enum PID

Process ID

8.8.2.5 PARENT

include std/pipeio.e
namespace pipeio
public enum PARENT

Set of pipes that are for the use of the parent

8.8.2.6 CHILD

include std/pipeio.e
namespace pipeio
public enum CHILD

Set of pipes that are given to the child - should not be used by the parent

8.8.3 Opening/Closing

8.8.3.1 process

include std/pipeio.e
namespace pipeio
public type process(object o)

Process Type

8.8.3.2 close

include std/pipeio.e
namespace pipeio
public function close(atom fd)

Close handle fd

Returns:

An integer, 0 on success, -1 on failure

Example 1:

integer status = pipeio:close(p[STDIN])

8.8.3.3 kill

include std/pipeio.e
namespace pipeio
public procedure kill(process p, atom signal = 15)

Close pipes and kill process p with signal signal (default 15)

Comments:

Signal is ignored on Windows.

Example 1:

kill(p)

8.8.4 Read/Write Process

8.8.4.1 read

include std/pipeio.e
namespace pipeio
public function read(atom fd, integer bytes)

Read bytes bytes from handle fd

Returns:

A sequence, containing data, an empty sequence on EOF or an error code. Similar to get_bytes.

Example 1:

sequence data=read(p[STDOUT],256)

8.8.4.2 write

include std/pipeio.e
namespace pipeio
public function write(atom fd, sequence str)

Write bytes to handle fd

Returns:

An integer, number of bytes written, or -1 on error

Example 1:

integer bytes_written = write(p[STDIN],"Hello World!")

8.8.4.3 error_no

include std/pipeio.e
namespace pipeio
public function error_no()

Get error no from last call to a pipe function

Comments:

Value returned will be OS-specific, and is not always set on Windows at least

Example 1:

integer error = error_no()

8.8.4.4 create

include std/pipeio.e
namespace pipeio
public function create()

Create pipes for inter-process communication

Returns:

A handle, process handles { {parent side pipes},{child side pipes} }

Example 1:

object p = exec("dir", create())

8.8.4.5 exec

include std/pipeio.e
namespace pipeio
public function exec(sequence cmd, sequence pipe)

Open process with command line cmd

Returns:

A handle, process handles { PID, STDIN, STDOUT, STDERR }

Example 1:

object p = exec("dir", create())