idlastro / FITS Binary Table Extensions I/O: FXBISOPEN

[Source code]

NAME
FXBISOPEN()
PURPOSE
Returns true if UNIT points to an open FITS binary table.
Explanation This procedure checks to see if the logical unit number given
by the variable UNIT corresponds to a FITS binary table opened
for read with the command FXBOPEN, and which has not yet been
closed with FXBCLOSE.
Use Result = FXBISOPEN(UNIT)
If FXBISOPEN(UNIT) THEN ...
Inputs UNIT = Logical unit number returned by FXBOPEN routine.
Must be a scalar integer.
Opt. Inputs None.
Outputs The result of the function is either True (1) or False (0),
depending on whether UNIT points to an open binary table or
not.
Opt. Outputs None.
Keywords None.
Calls FXBFINDLUN
Common Uses common block FXBINTABLE--see "fxbintable.pro" for more
information.
Restrictions None.
Side effects If UNIT is an undefined variable, then False (0) is returned.
If UNIT points to a FITS binary table file that is opened for
write, then False (0) is returned.
Category Data Handling, I/O, FITS, Generic.
Prev. Hist. None.
Written William Thompson, GSFC, 1 July 1993.
Modified Version 1, William Thompson, GSFC, 1 July 1993.
Version Version 1, 1 July 1993.
Converted to IDL V5.0   W. Landsman   September 1997