rtc(3I)

NAME
     _rtc, RTC, IRTC, IRTC_RATE - Returns clock register contents

SYNOPSIS
     C/C++:

     #include <intrinsics.h>
     long long _rtc (void);

     CF90 and MIPSpro 7 Fortran 90:

     RTC ()
     IRTC ()

     MIPSpro Fortran 77:

     IRTC_RATE()

IMPLEMENTATION
     UNICOS, UNICOS/mk, IRIX systems

     Cray C/C++, CF90, MIPSpro 7 Fortran 90, MIPSpro Fortran 77

STANDARDS
     C/C++ extension

     Fortran extension

DESCRIPTION
     The _rtc, RTC, and IRTC intrinsic functions return a real-time clock
     value.  The value is expressed as the number of clock ticks.  The
     IRTC_RATE function returns the clock rate of the IRTC and RTC
     functions.

NOTES
   C/C++
     Because _rtc is an intrinsic function, no externally visible library
     function is available for it.  The compiler generates inline code to
     produce the result.

   Fortran
     The names of these intrinsics cannot be passed as arguments.

     When RTC is called as a subroutine, it accepts the following argument:

     time   The real-time clock value is returned as a REAL(KIND=8) value.

     When IRTC is called as a subroutine, it accepts the following
     argument:

     itime  The real-time clock value is returned as an INTEGER(KIND=8)
            value.

     The RTC intrinsic function is outmoded.  For information on outmoded
     features and their preferred standard alternatives, see the Fortran
     Language Reference Manual, Volume 3.

     The use of RTC is not recommended on UNICOS or IRIX systems.  See the
     standard SYSTEM_CLOCK(3I) intrinsic subroutine for the preferred
     alternative.

FORTRAN RETURN VALUES
     RTC returns a 64-bit real value.  IRTC returns a 64-bit integer value.

     When using CF90 on a UNICOS system, RTC returns the low-order 46 bits
     of the clock register as a REAL(KIND=8) value.  IRTC returns the
     current content of the clock register as an INTEGER(KIND=8) value.
     The result of IRTC may exceed 2**(46)-1 and must not be used in
     multiplication, division, or conversion to real unless the value is
     typed as a 64-bit integer in the CF90 program or -O nofastint is
     specified on the f90(1) command line.  Addition and subtraction are
     unaffected.

     On IRIX systems, RTC returns the low-order 52 bits of the system clock
     expressed as a REAL(KIND=8) value.  IRTC returns the system clock as
     an INTEGER(KIND=8) value.  IRTC_RATE returns the number of IRTC and
     RTC clock ticks per second in an INTEGER(KIND=8) value.  IRTC is the
     fastest nonwrapping clock.

SEE ALSO
     A complete list of C/C++ intrinsic functions available on UNICOS and
     UNICOS/mk systems is in the Cray C/C++ Reference Manual.

     f90(1), SECOND(3F), SYSCLOCK(3F), SYSTEM_CLOCK(3I), TSECND(3F)

     Intrinsic Procedures Reference Manual for the printed version of this
     man page.