Module stream

Predicates for input/output stream

Predicate

open_null_stream/1: Open an empty stream.
open_socket_stream/3: Open a socket stream.
open_pty_stream/3: Open a pseudo-terminal stream.
open_process_stream/4: Open a process stream.
open_file_stream/3: Open a file stream.
open_server_stream/2: Open port for server.
accept_connection/1: Accept connection to server stream Handle.
close_connection/1: Close connection to server stream Handle.
write_string/2: Write a string into a stream handle.
writeln_string/2: Write a string into a stream handle. Also write a new line character.
write_string_list/2: Write a list of strings (or integers) into a stream handle.
writeln_string_list/2: Write a list of strings (or integers) into a stream handle. Also write a new line character.
read_string/3: Read a string from a handle.
readln_string/2: Read a string from the stream. It stops when find a new line character.
write_stream/2: Write the binary data into the stream.
read_stream/3: Read the binary data from the stream.
close/1: Close a stream .
flush_output/1: Flush the stream's buffer.
eof_stream/1: Says if the end of the stream has been reached.
stdin_stream/1: Return the handle of stdin.
stdout_stream/1: Return the handle of stdout.
stderr_stream/1: Return the handle of stderr.

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The predicate will fail in the next cases.

The port numbe can't be reached in the designated host.
Can't connect to the host's port.
Maximum number of open streams exceeded．
Cannot allocate stream Handle.

Open a socket stream.

> :- open_socket_stream("dallmayr", 12345, X).

open_pty_stream/3

Format open_pty_stream(+Name, +Args, -Handle)

Arguments

`+Name`	string	Command name.
`+Args`	list of strings	Arguments of the command
`-Handle`	handle_ptystream	PTY stream.

Open a pseudo-terminal stream to communicate with an external command through standard I/O.

open_process_stream/4

Format open_process_stream(+Name, +Args, +Mode, -Handle)

Arguments

`+Name`	string	Command name.
`+Args`	list of strings	Arguments of the command.
`+Mode`	string	Open mode (i/o)
`-Handle`	handle_processstream	process stream.

Open a stream to communicate with an external command via standard input or output.

open_file_stream/3

Format open_file_stream(+Name, +Mode, -Handle)

Arguments

`+Name`	string	File name.
`+Mode`	string	Open mode of the file.
`-Handle`	handle_filestream	File stream.

Note

Below is the list of modes.

"r" : Open just for read. Will fail if file does not exists。
"w" : Opens just for write. The previous file is overwriten.
"a" : Open it in exclusive mode.
"r+" : Opens for read. Creates a new file if doesn't exists.
"w+" : Opens for write. Creates a new file if doesn't exists.
"a+" : Opens for read and write．Write from the end of the file.
The reasons because the predicate can fail are.

The open mode of the file name is not applicable.
For any reason the file can't be open.
Maximum number of open streams exceeded．
Can't create the stream handle.

Open a file stream.

 > :- open_file_stream("/etc/passwd", "r", X).

open_server_stream/2

Format open_server_stream(+Port,-Handle)

Arguments

`+Port`	integer ：port number of server
`-Handle`	handle_serverstream ：stream handle

Note

This predicate fails on the following condition.

Cannot open port.

Open port for server.

> ?- open_server_stream(8500, X).

accept_connection/1

Format accept_connection(+Handle)

Arguments

+Handle handle_serverstream ：stream handle

Accept connection to server stream Handle.

> ?- open_server_stream(8500, X), accept_connection(X).

close_connection/1

Format close_connection(+Handle)

Arguments

+Handle handle_serverstream ：stream handle

Close connection to server stream Handle.

write_string/2

Format write_string(+Handle, +String)

Arguments

`+Handle`	handle_stream	Stream handle
`+String`	string	String

Note

The reasons because the predicate can fail are.

The stream handle is invalid.
The second argument is not a string.

Write a string into a stream handle.

> :- open_file_stream("hoge", "w", X), write_string(X, "poge").

writeln_string/2

Format writeln_string(+Handle, +String)

Arguments

`+Handle`	handle_stream	Stream handle
`+String`	string	String

Note

The reasons because the predicate can fail are.

The stream handle is invalid.
The second argument is not a string.

Write a string into a stream handle. Also write a new line character.

> :- open_file_stream("hoge", "w", X), writeln_string(X, "poge").

write_string_list/2

Format write_string_list(+Handle, +List)

Arguments

`+Handle`	handle_stream	Stream handle
`+List`	list	List of string or integers

Note

The reasons because the predicate can fail are.

The stream handle is invalid.
The second argument is not a list of strings or integers.

Write a list of strings (or integers) into a stream handle.

writeln_string_list/2

Format writeln_string_list(+Handle, +List)

Arguments

`+Handle`	handle_stream	Stream handle
`+List`	list	List of string or integers

Note

The reasons because the predicate can fail are.

The stream handle is invalid.
The second argument is not a list of strings or integers.

Write a list of strings (or integers) into a stream handle. Also write a new line character.

read_string/3

Format read_string(+Handle, +Len, -String)

Arguments

`+Handle`	handle_stream	Stream handle
`+Len`	integer	Length of the string
`-String`	string	Readed string.

Note

The reasons because the predicate can fail are.

The stream handle is invalid.
The second argument is not an integer.
The stream is closed.

Read a string from a handle.

> :- open_file_stream("/etc/passwd", "r", X), read_string(X, 10, Y).

readln_string/2

Format readln_string(+Handle, -String)

Arguments

`+Handle`	handle_stream	Stream handle
`-String`	string	Readed string.

Note

The reasons because the predicate can fail are.

The stream handle is invalid.
The stream is closed.

Read a string from the stream. It stops when find a new line character.

> :- open_file_stream("/etc/passwd", "r", X), readln_string(X, Y).

write_stream/2

Format write_stream(+Handle, +Data)

Arguments

`+Handle`	handle_stream	Stream handle.
`+Data`	list of integers	The data. A list of values in the range of 0 - 255.

Note

The reasons because the predicate can fail are.

The stream handle is invalid.

Write the binary data into the stream.

> :- open_file_stream("/etc/passwd", "r", X), readln_string(X, Y).

read_stream/3

Format read_stream(+Handle, +Len, -Data)

Arguments

`+Handle`	handle_stream	Stream handle.
`+Len`	integer	Length of the data.
`-Data`	list of integers	Read data.

Note

The reasons because the predicate can fail are.

The stream handle is invalid.
The second argument is not an integer.
The stream is closed.

Read the binary data from the stream.

> :- open_file_stream("/etc/passwd", "r", X), read_stream(X, 10, Y).

close/1

Format close(+Handle)

Arguments

+Handle handle_stream Stream handle.

Note

The reasons because the predicate can fail are.

The stream handle is invalid.

Close a stream .

> :- close(X).

flush_output/1

Format flush_output(+Handle)

Arguments

+Handle handle_stream Stream handle.

Note

The reasons because the predicate can fail are.

The stream handle is invalid.

Flush the stream's buffer.

> :- flush_output(X).

eof_stream/1

Format eof_stream(+Handle)

Arguments

+Handle handle_stream Stream handle.

Note

The reasons because the predicate can fail are.

The stream handle is invalid.

Says if the end of the stream has been reached.

> ?- eof_stream(X).

stdin_stream/1

Format stdin_stream(-Handle)

Arguments

-Handle handle_stream Stream handle.

Return the handle of stdin.

> :- stdin_stream(X).

stdout_stream/1

Format stdout_stream(-Handle)

Arguments

-Handle handle_stream Stream handle.

Return the handle of stdout.

> :- stdout_stream(X).

stderr_stream/1

Format stderr_stream(-Handle)

Arguments

-Handle handle_stream Stream handle.

Return the handle of stderr.

> :- stderr_stream(X).

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This document is automatically created by lildoc on Fri Sep 24 14:13:58 2004