One can tell the ILE c and c++ compilers whether to perform i/o to IFS files or a native file system by specifying the SYSIFCOPT(*NOIFSIO) or SYSIFCOPT(*IFSIO) parameters on the corresponding compile commands.
Is there any way to choose this option at runtime?
Sadly this is not possible as far as I know. Compilation creates "different object" for different compile flags. For example, the fopen behave differently according to this flag and it is set in compile time only.
This was first published in February 2009