BLIOVLSIZ()                   Get current size of overlay pool memory.
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 Function : Get current size of overlay pool memory.

 Syntax   : nlValue = BLIOVLSIZ()

 Return   : Overlay Pool Current Size

 This function returns the size of the overlay area as it was actually
 allocated when the program started running. The default size is the most
 recent of the value set at link time with the BLINKER OVERLAY OPSIZE nnn
 command and the /OOnnn setting of the BLINKER environment variable at
 runtime. This size may be modified in one of two ways:

 If the BLINKER OVERLAY PAGEFRAME ON command was used at link time, or the
 /OP1 setting in the BLINKER environment variable is set at runtime, then if
 an EMS pageframe is available and the default OPSIZE is less than 64kb then
 the size of the overlay area will be expanded to use as much of the
 pageframe as possible. This new size will then be the size returned by the
 BLIOVLSIZ() function.

 If the use of the pageframe is not possible or has been disabled, and
 provided the use of UMBs has not been disabled through the use of the
 BLINKER OVERLAY UMB OFF command at link time or the /OU0 setting of the
 BLINKER environment variable at runtime, then Blinker will attempt to
 allocate a UMB at least as large as the default OPSIZE. If this is
 successful then the size of the overlay area will be expanded to use as much
 of the UMB as possible. This new size will then be the size returned by the
 BLIOVLSIZ() function.

 If neither of these methods is possible, or both have been disabled, then
 the size allocated will be the default OPSIZE.

 CA-Clipper Summer '87 DYNAMIC method note:

 When using the BLINKER OVERLAY DYNAMIC method of overlay allocation, this
 value reflects the exact amount of memory being used by Blinker for overlays
 at the current time. At the start of an application this will be zero, and
 the value will increase until it reaches the operating size set by BLINKER
 OVERLAY OPSIZE <size> and returned by BLIOVLOPS().

 Once it has reached this size it will stabilize for the rest of the
 application until a call to BLIOVLCLR(). When a call to BLIOVLCLR() is made,
 all inactive overlays are discarded and the memory is returned to
 CA-Clipper, so the current size will decrease to the size of just the active
 overlays. In the best case of BLIOVLCLR() being called from the root then
 BLIOVLSIZ() should actually return to zero.

 Example:

    * Get the current overlay pool size.
    *
    ? "The current overlay pool size is"
    ?? BLIOVLSIZ(), " bytes"