FREE
This command is used to free the memory held by a field that has
been read from a data file.
Widget:
- There is no widget for this command.
Command:
Arguments :
- field: the field name which will be deleted from memory.
Examples :
Notes :
- This command is most useful when machine memory limits are reached, and no
more fields may be read in. If a data file, which has been previously read
containts 4 fields (variables), i.e. A, B, C and D, each one of these variables
has assigned location in the memory. Let's suppose we can picture their sequence
in the memory as ...A...B...C...D.... (There may be a gap between variables
since IVE allocates additional memory for its own use from time to time). If
for example user types in command 'FREE = B', then space used by B is freed up,
thus: ...A...free...C...D.... The total allocated memory is however still the
same (from A to D). This is also true even if the last field was freed up (i.e.
'FREE = D' which results in ...A...B...C...) and there apparently is more memory
available. Freeing of memory doesn't show up as long as IVE is running. If a new
field is being invoked, or a new file is being read in, then the freed space can
be used if the new variable uses equal or lesser amount of memory. In our case,
we were left with ...A...free...C...D.... The new file contains variable X. If X
takes less memory than B, then it will fit into the vacant slot
...A...X...C...D... and the total allocated memory remains the same. If X takes
more memory than B, it will be positioned at the end,
...A...free...C...D...X.... If the goal of freeing the space was to avoid
exceeding a memory size limit, then in the latter example X can not be read in -
a larger block of continuous memory has to be freed.
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