The INPUT_PORT macro takes the task’s input port selected by portid and associates the bound channel with an identifier; this identifier is used to create an external variable of type CHAN. The macro may be used as a declaration in any file used to build a task. Note that as the variable is external its name must be unique or the linker will report errors.
Portid can be:
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| • | an integer constant index into the task’s input port vector, selecting a particular port; |
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| • | the name of a CONNECT statement in the configuration file, selecting the input port specification for this task. |
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See also OUTPUT_PORT.
For example, given the following extract of a configuration file:
TASK A ....
TASK B .... INS=4
CONNECT control A[1] B[2]
The main function of B could include the following:
INPUT_PORT(control, control_in)
INPUT_PORT(3, data_in);
main(int argc, char *argv[], char *envp[],
CHAN *in_ports[], int ins,
CHAN *out_ports[], int outs) {
...
chan_in_message(16, b, in_ports[2]);
chan_in_message(16, b, &control_in); // same as above
chan_in_message(12, b, in_ports[3]);
chan_in_message(12, b, &data_in); // same as above
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