To test whether data is on the return port, you should try using the pending port. This function returns True when the data is pending for a specified number of microseconds. If the time limit is reached, the function returns False. You can also use the timeout port to find out how much time has elapsed since the call was made. If the data is not on the return port, you can use the wait-for-data port instead.
Functions that print values to input and output ports
The following section describes the procedures for creating, accessing, and altering the input and output ports. For each of these types, the “port” argument is either the string itself, or a fixed value. The ‘print-to’ function prints the output to the current port, while ‘print-to-file’ prints the value to a file. Depending on the port, the arguments may not be strings.
A port handler is associated with each port. Each port receives a specific message that corresponds to the operation performed on it. For example, read-char must return a character, while close-port must return an object that is eof. A user-defined port may also accept additional messages. These messages are passed to the S-function block during the simulation loop. Using the port-handler, the code can retrieve and print values to an input or output port.
There are two types of output-port-buffers: textual and binary. For textual ports, the output-buffer-size field must be an integer; the value of n must be less than the number of characters in the string. For binary ports, the value of n is zero. The output-port-index field should be either zero or a positive integer. Both functions will return the value of the difference between the size and index fields.
Functions that print values to lookup ports
If you have an unconnected lookup transformation, you can use it to fetch a lookup result from a cached dimension table. It can also be used to update a dimension table over time, as it queries a lookup source based on a condition. The Lookup transformation can return multiple columns from the same row. A lookup port can also be connected to more than one transformation. To use it, you can call an Integration Service, which queries a lookup source based on a condition, and then passes the returned value to a Lookup transformation.
The Integration Service performs lookups by requesting the data from a table with an index. The lookup source must contain columns that match the lookup condition. In case the lookup source is unconnected, the Transformation Service returns only one column from the source. When this condition is met, it issues a SELECT statement to return the corresponding row. In this case, the Transformation Service uses a cached lookup source that returns only the values matching the conditions.
Functions that print values to read-only ports
A C function that prints the value of an unsigned int into a read-only port is called a wrapper function. The wrapper function takes as arguments an unsigned int and a size_t. It then assumes that the data port is stable after reset and implements the print function with an associated valid port. Here are some examples of wrapper functions. In addition to the print function, you can also create your own wrapper functions by using the following C code.
Functions that print values to unconnected ports
The mdlInitializeSizes command sets the size requirements for various signal types. The S-function block’s mdlInitializeSizes routine sets the sizes for different types of signals. An S-function can access contiguous input and output ports. An unconnected port will fail this test if it is not connected to the ground/terminator block.