APL_FAST_FCHK

This parameter specifies whether Dyalog APL should optimise ⎕FCHK by allowing it to reliably determine whether a component file had been properly untied and therefore does not need to be checked (this is overridable using the ⎕FCHK option force).

Optimising ⎕FCHK in this way has a performance impact on ⎕FUNTIE and it is recommended this optimisation is switched off if your application frequently ties and unties files.

This only affects component files with journaling enabled.

The values of the parameter are:

The default value of the parameter is 0 on all platforms. On Windows, setting the value 1 has no effect.