How to make calls to error_() routine, JGOFS v1.5

/by Warren J. Sass/

*Changing your (non-distributed) method:* /Remember: all distributed
methods for v1.5 already have this modification/

   1. If your method is a modification of a distributed method,
      (e.g.,def), replace function err() with the following code:

	void err(s,t)
	char *s,*t;
	void error_();
	  /*  Let outer print all error messages		*/
	  exit(1);	/*  Should not reach this statement	*/

   2. If your method writes error text to stdout and then immediately
      exits, each print statement involved should be replaced by a call:


      where string1 and string2 are both pointers to character strings.
      Between them, the 2 strings should make up the error text
      previously found in the replaced print statement. error_() prints
      the strings with a colon between them. error_() should be declared
      once in your source code with a statement:

	void error_();

      This statement should precede the first call to error_(). The exit
      calls that follow the print statements (and will now follow the
      error_() calls) are superfluous, since error_() does not return to
      inner. However, these exit calls can remain in place.

   3. If your method writes error text to stdout and does *NOT exit*,
      you cannot use error_(), since error_() will not return to inner. 


*Why use error_() instead of writing error text to stdout?*

In an HTTP environment, text cannot be written to stdout until the
server has been informed that text will be forthcoming. error_()
guarantees that the server has been properly informed. Text sent at the
wrong time can produce a "Server 500" error.

When doing plots or other applications from the "Plotting and other
options" menu, the method must inform the application that the text that
follows represents information about an error and is not just more data.
error_() makes this distinction on behalf of the method.