Unfortunately, no, it can only be set upon driver (e.g.,
devb-eide) startup. There are several several alternative solutions
that you might consider:
1.) Restart your disk driver, e.g. devb-eide. If you can
afford to be without access to the disk for several seconds, this can be
done by putting devb-eide and it's dependencies, e.g.
io-blk.so,
fs-qnx6.so,
into a ramdisk area. This can be done by copying them to /dev/shmem,
or using the more full-featured devb-ram. You might also need utilities
like sleep or waitfor, to indicate when it is safe to begin using the
driver after restarting it. See the devb-eide documentation in the
Neutrino Utilities reference for information on starting and using
devb-eide, or other disk drivers and file-systems.
2.) Run your system using commit=low, but when important
information needs to be forcibly committed, open the file using O_SYNC,
or use the sync() or fsync() functions to request the commit.
