NAME:  errno, _rc2Errno - number of last error

SYNOPSIS 
       #include <errno.h>  
       #include <sys/errnox.h>  

 DO NOT EXPLICITLY DECLARE
       #define errno (*_errno())
       extern int *_errno(void);
       const char *const sys_errlist[];
       const int sys_nerr;

 EXTENSIONS [not portable, interface may change]
       #define OS2_API32
       #define INCL_DOS
       #include <os2.h>  

       int _rc2Errno(APIRET rc);

DESCRIPTION
       ANSI C90 errno is a modifiable thread-local lvalue of type int,
       indicating the last error. It is usually implemented as a macro.

  NOTES
       Successful library calls are never allowed to change errno.
       To determine if an error occured, application programs must zero
       errno before calling a library function.

IMPLEMENTATION
       See sys/errno.h for available errno values.

       The _rc2Errno() macro translates kernel error return codes
       to ANSI errno values. This interface may change and is not portable.

BUGS
       Historic implementations of Unix-like operating systems incorrectly
       require the definition of 'int errno'. This violates the ANSI 
       standard and is not allowed in this implementation.

