OSERROR(3C)                                                        OSERROR(3C)


NAME
     oserror, setoserror, goserror - get/set system error

C SYNOPSIS
     #include <errno.h>

     int oserror(void);

     int setoserror(const int err);

     int goserror(void);

DESCRIPTION
     Most system calls and many system library functions set a global error
     value errno when they encounter an error.  For single threaded
     applications a global is sufficient.  For multi-threaded applications a
     global error value loses much of its meaning, since multiple threads may
     be updating the same value at the same time.  When a process turns
     multi-threaded (by calling sproc(2)) a per-thread location to store the
     error value is created.  sproc(2) and intro(2) have more information on
     error handling.

     These routines provide access to the error values.  oserror returns the
     value in the global error location for single threaded applications and
     returns the value in the per-thread error location for multi-threaded
     applications.  This is equivalent to compiling the application with the
     feature test macro _SGI_MP_SOURCE defined and simply referencing errno.

     setoserror sets both the global error location and the per-thread error
     location for the calling thread.  This is primarily used by library
     routines.

     goserror always returns the value in the global error location.

     Possible errors are listed in errno.h.

RETURN VALUE
     oserror, goserror, and setoserror return the current system error.

SEE ALSO
     intro(2), sproc(2), perror(3C).


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