|GNU Octave Manual Version 3|
by John W. Eaton, David Bateman, Søren Hauberg
Paperback (6"x9"), 568 pages
RRP £24.95 ($39.95)
11.7.4 Function Locking
It is sometime desirable to lock a function into memory with the
mlock function. This is typically used for dynamically linked
functions in Oct-files or mex-files that contain some initialization,
and it is desirable that calling
clear does not remove this
As an example,
my_function from being removed from memory, even if
clear is called. It is possible to determine if a function is
locked into memory with the
mislocked, and to unlock a function
munlock, which the following illustrates.
mlock ("my_function"); mislocked ("my_function") => ans = 1 munlock ("my_function"); mislocked ("my_function") => ans = 0
A common use of
mlock is to prevent persistent variables from
being removed from memory, as the following example shows:
function count_calls() persistent calls = 0; printf ("'count_calls' has been called %d times\n", ++calls); endfunction mlock ("count_calls"); count_calls (); -| 'count_calls' has been called 1 times clear count_calls count_calls (); -| 'count_calls' has been called 2 times
It is, however, often inconvenient to lock a function from the prompt,
so it is also possible to lock a function from within its body. This
is simply done by calling
mlock from within the function.
function count_calls () mlock (); persistent calls = 0; printf ("'count_calls' has been called %d times\n", ++calls); endfunction
mlock might equally be used to prevent changes to a function from having
effect in Octave, though a similar effect can be had with the
- Built-in Function: mlock (name)
- Lock the named function into memory. If no function is named
then lock in the current function.
See also munlock, mislocked, persistent
- Built-in Function: munlock (fcn)
- Unlock the named function. If no function is named
then unlock the current function.
See also mlock, mislocked, persistent
- Built-in Function: mislocked (fcn)
- Return true if the named function is locked. If no function is named
then return true if the current function is locked.
See also mlock, munlock, persistent
|ISBN 095461206X||GNU Octave Manual Version 3||See the print edition|