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AST_CURRENTTIME - Return the current system time

Description:
This routine returns the current system time, represented in the form specified by the supplied TimeFrame. That is, the returned floating point value should be interpreted using the attribute values of the TimeFrame. This includes System, TimeOrigin, LTOffset, TimeScale, and Unit.
Invocation:
RESULT = AST_CURRENTTIME( THIS, STATUS )
Arguments:
THIS = INTEGER (Given)
Pointer to the TimeFrame.
STATUS = INTEGER (Given and Returned)
The global status.
Returned Value:
AST_CURRENTTIME = DOUBLE
Notes:
  • Values of AST__BAD will be returned if this function is invoked with STATUS set to an error value, or if it should fail for any reason.

  • It is assumes that the system time (returned by the C time() function) follows the POSIX standard, representing a continuous monotonic increasing count of SI seconds since the epoch 00:00:00 UTC 1 January 1970 AD (equivalent to TAI with a constant offset). Resolution is one second.

  • An error will be reported if the TimeFrame has a TimeScale value which cannot be converted to TAI (e.g. "angular" systems such as UT1, GMST, LMST and LAST).

  • Any inaccuracy in the system clock will be reflected in the value returned by this function.


next up previous 264
Next: AST_CURVE - Draw a geodesic curve
Up: AST Routine Descriptions
Previous: AST_COPY - Copy an Object

AST A Library for Handling World Coordinate Systems in Astronomy
Starlink User Note 210
R.F. Warren-Smith & D.S. Berry
24th May 2011
E-mail:ussc@star.rl.ac.uk

Copyright (C) 2009 Science \& Technology Facilities Council