After an error is detected, it can be handled in different ways.
The web browser uses two ways: trying again, and terminating the
program with an error message. If the user gave a zero-length web
address, the program asks again.
If you want to terminate the program, this is a common code
snippet:
if(result_of_something == 0)
{
werror("Failed to open the file called '" +
file_name + "'\n");
exit(1);
}
The call to exit will terminate the program. An argument
greater than 0 to exit, or as a return value from
main, means that the program failed in some way.
The built-in function werror prints a string on the
standard error output (Stdio.stderr) instead of the
normal standard output (Stdio.stdout). This has a
higher chance of being seen by the user, since if you re-direct the
output from a program, like this:
webbrowser.pike www.rocksen.com > output.txt
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then the standard output will be printed to the file
output.txt, but the standard error output will still be
printed on the screen.
