TSX FUNCTIONS

(make-client-socket host port)
host: string (IP address or host name)
port: integer number

Returns a socket which is already connected to the specified host and port, or #f if the connection could not be performed.

(make-server-socket port)
port: integer number

Returns a socket which is bound to the specified port on the local machine, and ready to accept connections. If the socket could not be created (e.g., because the port is already in use, or it is a privileged port and the user has no permissions on it), #f is returned.

(recv! sock buff)
sock: socket obtained with make-client-socket or accept
buff: string

Waits for received data through the specified socket, and stores it on the buffer. The return value indicates the number of received bytes. This call blocks until some data is received, but does not guarantee that buff gets completely filled. If an error occurs (e.g., the other peer disconnects) then #f is returned.

(recv-new-string sock)
sock: socket obtained with make-client-socket or accept

Waits for received data through the specified socket, and returns it in a new string. This call blocks until some data is received. If an error occurs, then #f is returned.

(send sock buff)
sock: socket obtained with make-client-socket or accept
buff: string

Sends the data contained in the string through the socket. It returns the number of transmitted bytes (could be different than the size of the string!), or #f if an error occured (e.g., the other peer disconnected).

(accept server-sock)
server-sock: socket obtained with make-server-socket

Waits until a connection is received on the specified server socket, and returns the connected socket. If an error occurs (e.g., the network interface shuts down), it returns #f instead.

(close-socket sock)
sock: socket obtained with make-server-socket, make-client-socket or accept

The socket is closed. No further calls should be performed on this socket.

(sock-is-data-ready? sock)
sock: socket obtained with make-server-socket, make-client-socket or accept

This function allows non-blocking operation with sockets. It returns #t if data is available for reception on this socket, and #f if no data has been received.

(sock-peek sock)
sock: socket obtained with make-server-socket, make-client-socket or accept

This function returns (as a newly created string) the data received in this socket. The information is not removed from the input queue.

Filesystem Functions

(file-size filename)
filename: string

This function returns the size (in bytes) of the indicated file, or #f if the file does not exists or is not accessible to the requesting user.

(file-exists? filename)
filename: string

This function returns #t if the indicated file exists, and #f if it does not exists or it is not accessible to the requesting user.

(delete-file filename)
filename: string

Removes the specified file. It returns #t if the operation succeeds, or #f otherwise (e.g., because the file is read-only, or because the file does not exist).

(open-dir-stream path)
path: string

Opens a "directory stream" on the provided directory path. This stream will provide all the files within the directory, using the function read-dir-entry. The stream should be closed at the end with close-dir-stream.

(read-dir-entry dirstream)
dirstream: directory stream, obtained with open-dir-stream.

It returns the name of the following directory entry, or eof if all the entries were provided. Check the return value with with eof-object?.

(close-dir-stream dirstream)
dirstream: directory stream, obtained with open-dir-stream.

Close directory stream. No further calls to read-dir-entry should be performed.

Time Functions

(gettimeofday)
Returns a list containing the number of seconds from the beginning of the day, and microseconds within the current second.

(usleep microsec)
microsec: integer

Suspends execution of the calling thread during the specified number of microseconds.

Miscellaneous functions

(system command)
command: string

Executes a command on the /bin/sh shell. Returns #f if it is unable to run /bin/sh or another error occurs, or an integer return code which is the value returned by the command to the shell.