Specifications

Chapter 18. TCP/IP
481
Syntax:
CALL "SOCKET.FN3" .fcSelect MAXFD%, READFDSET$,
WRITEFDSET$, EXCEPTFDSET$, TIMEOUT, RESULT%
Description: This function waits for changes in the socket identifier sets (read, write,
and exception conditions) for the specified socket identifiers.
The only exception condition is out of band data.
BSD4.4 socket API equivalent: This function is equivalent to the BSD4.4
socket API select() function.
Parameters:
MAXFD% Number of socket identifiers + 1
READFDSET$ Socket identifier set to monitor for read
WRITEFDSET$ Socket identifier set to monitor for write
EXCEPTFDSET$ Socket identifier set to check for exception conditions
TIMEOUT Waiting period (in seconds)
The waiting period (
TIMEOUT) must be one of the following values:
Return value:
RESULT% Number of sockets that are ready.
After a timeout, RESULT% contains 0.
Run-time errors:
.fcSelect Monitor socket requests
.soNoWait -1 No waiting period
.soNotTOut 0 No timeout
Other time interval in seconds
Error code Meaning
105h
Power-off detected
106h
An internal error has occurred in the TCP/IP module during data
transmission.
107h
The TCP/IP module has not been initiated.
108h
The memory for the TCP/IP module has became insufficient dur-
ing data transmission.
209h
Socket identifier is invalid.
216h
A parameter is invalid.