SysSockSelectΒΆ
This function of type DINT calls the function select of the operating system to check whether one or several sockets are ready for certain communication actions. The group of sockets, to which this request should be applied, can be defined via the structure SOCKET_FD_SET.
The function will return the result of the select function.
| Variable | Data type | Description |
|---|---|---|
| diWidth | DINT | Size of structure SOCKET_FD_SET. |
| fdRead | DWORD | Optionally a pointer to the structure defining the socket set for which the status of the read actions should be checked. You also can pass 0. Structure SOCKET_FD_SET see below (corresponding parameter e.g. in Win32: readfds) |
| fdWrite | DWORD | Optionally a pointer to the structure, defining the socket for which the status of the write actions should be checked. You also can pass 0. Structure SOCKET_FD_SET see below (corresponding parameter e.g. in Win32: writefds) |
| fdExcept | DWORD | Optionally a pointer to the structure, defining the socket for which the error status should be checked. You also can pass 0. Structure SOCKET_FD_SET see below (corresponding parameter e.g. in Win32: exceptfds) |
| ptvTimeout | DWORD | Maximum time which the SysSockSelect function will wait for an answer; Structure SOCKET_TIMEVAL, see below (corresponding parameter e.g. in Win32:timeout) |
Structure SOCKET_FD_SET
| fd_count: | UDINT; | (* Number of sockets *) |
| fd_array: | ARRAY [0..63] OF DINT; | (* Field with socket descriptors *) |
Structure SOCKET_TIMEVAL:
| tv_sec: | DINT; | (* seconds *) |
| tv_usec: | DINT; | (* microseconds *) |