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| Related Syntax | Related Concepts | Other Library Functions | ||||||||
| function | TCPConnectionGetCharacters |
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Library: omtcp - TCP/IP client and server support
Include: omtcp.xin |
Return type: String Returns: Characters read from the TCP connection. |
define external stream function TCPConnectionGetCharacters
value TCPConnection this-TCPConnection
size value integer minimum-read-length optional
variable-to value integer maximum-read-length optional
timeout value integer timeout-in-milliseconds optional
as TCPConnectionGetCharacters
This function reads characters received from a source on the TCP connection object.
There are four combinations for specifying the size and variable-to values, as follows:
TCPConnectionGetCharacters returns as many characters as it has available, as long as it has at least one character. It will wait (only for as long as the timeout value if one is specified) for at least one character, only if it has no characters to return.
TCPConnectionGetCharacters reads and returns exactly minimum-read-length characters. If a timeout value is specified and is exceeded, it will return immediately with the (zero or more) characters it has available. It will also set the TCP connection to be in error.
TCPConnectionGetCharacters reads as many characters as it has available, as if neither size nor variable-to were specified, except that if it has more than maximum-read-length available, it will only return maximum-read-length and will save any remaining characters for a subsequent read.
TCPConnectionGetCharacters reads at least minimum-read-length characters, but will return up to maximum-read-length characters, if it has them available. Like the size value only case, it can timeout in reading the first minimum-read-length characters, but will not do so once that many have been read. It is an error for the size value to be greater than the variable-to value.
If the passed TCP connection object is closed or was never connected, then this function returns zero characters. At the same time, it sets the TCP connection to be in error. If an error is encountered during reading, either zero characters or those already read (if any) are returned, as seems appropriate, and the TCP connection object is set to be in error.
Note that difficulties inherent in deriving multiple sources from a connection apply equally to using TCPConnectionGetCharacters when a TCPConnectionGetSource derived source is also active. Note, however, that sequential uses of TCPConnectionGetCharacters are allowed. It is also guaranteed that a TCPConnectionGetCharacters will only ever read the characters it returns from a source. Any following characters are available to the next TCPConnectionGetSource, TCPConnectionGetCharacters, or TCPConnectionGetLine.
Any attempt to do a TCPConnectionGetCharacters when the associated TCP connection has been closed using TCPConnectionClose is in error, and will set the TCP connection to be in error.
Any attempt to do a TCPConnectionGetCharacters when there is already an active source derived from TCPConnectionGetSource is not allowed and will result in an OmniMark external function exception.
Arguments:
TCPConnectionGetCharacters will read.
TCPConnectionGetCharacters will read.
Example
local TCPConnection TCP-Conn
set TCP-Conn to TCPConnectionOpen on "localhost" at 5300
repeat
exit unless TCPConnectionIsConnected TCP-Conn
output TCPConnectionGetCharacters TCP-Conn
again
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