Arguments to main

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The standard declaration for a task’s main function is:

int main(int argc, char *argv[], char *envp[],

CHAN * in_ports[], int ins,

CHAN *out_ports[], int outs)

	argc	number of command-line arguments. This is always zero for stand-alone tasks.
	argv	command-line arguments
	envp	always null
	in_ports	vector of input ports
	ins	number of entries in the vector in_ports
	out_ports	vector of output ports
	outs	number of entries in the vector out_ports

For example, a simple task might accept a stream of values on an input port representing characters, convert each character to upper case, and output the resulting stream of characters on an output port. The code for this is shown below; if you want to experiment you can find the source text in the file:

<3L>My Designs\examples\Sundance\example-2\upc.c.

#include <chan.h>

#include <ctype.h>

#include <stdio.h> // for EOF

main(int argc, char *argv[], char *envp[],

CHAN * in_ports[], int ins,

CHAN *out_ports[], int outs) {

int c;

for (;;) {

chan_in_word(&c, in_ports[0]);

if (c == EOF) break; // terminate task

chan_out_word(toupper(c), out_ports[0]);

}