Operation Would Block Error

When attempting to perform a network operation, such as sending or receiving data, it fails with an error indicating that the operation would block.

More Information

When a non-blocking (asynchronous) socket attempts to perform an operation that cannot be performed immediately, error 10035 will be returned. This error is not fatal, and should be considered advisory by the application. This error code corresponds to the Windows Sockets error WSAEWOULDBLOCK.

When reading data from a non-blocking socket, this error will be returned if there is no more data available to be read at that time. In this case, the application should wait for the OnRead event to fire which indicates that more data has become available to read. The IsReadable property can be used to determine if there is data that can be read from the socket.

When writing data to a non-blocking socket, this error will be returned if the local socket buffers are filled while waiting for the remote host to read some of the data. When buffer space becomes available, the OnWrite event will fire which indicates that more data can be written. The IsWritable property can be used to determine if data can be written to the socket.

It is important to note that the application will not know how much data can be sent in a single write operation, so it is possible that if the client attempts to send too much data too quickly, this error may be returned multiple times. If this error occurs frequently when sending data it may indicate high network latency or the inability for the remote host to read the data fast enough.

See Also

Article 100025: Blocking Operation in Progress Error