// report_err.c from [Jumpstart]
//
// THIS CODE WILL COMPILE ON CYGWIN AND SOLARIS
// BUT IT WILL NOT LINK on CYGWIN because the 
// 	extern errno is undefined.
//
// SOLUTION: in cygwin, you need to include another file
//		#include <errno.h>
//
// 	Somehow, cygwin gcc knows how to autoimport "sys_nerr"
// 	and "sys_errlist".
//

	#include <stdio.h>

	//============================================
	void report_err(char * prefix)
	{
	   extern int errno;
	   extern int sys_nerr;    // size of array sys_errlist
	   extern char *sys_errlist[];

	   if (prefix != NULL)
	   	printf("%s: ", prefix);
	   if (0 < errno && errno < sys_nerr)
	   	printf("%s\n ", sys_errlist[errno]);
	   else
	   	printf("unknown error\n");
	   exit(1);
	}

	main()
	{
		report_err("TESTING");
	}
	//============================================