Shankar Swamy (shankar.n.swamy++at++boeing.com)
Thu, 4 Mar 1999 19:24:31 -0800
This is about pfFlux.
The man page says:
" ... PFFLUX_WRITE_ONCE controls what happens when pfFlux::getWritableData is
called and there is already a readable data buffer with the current frame
number. Setting it to PF_ON will cause NULL to be returned from
pfFlux::getWritableData. Setting it to PF_OFF will cause the pointer to
the readable data buffer to be returned. ..."
Suppose that I have a readable data buffer, and then decide that
I want to update it. Now, if PFFLUX_WRITE_ONCE is set to PF_ON,
getWritableData() will return a pointer to readable data
- is that correct? Is that pointer good for writing the data?
Else what good is that and how do I update the data in this case?
It sounds strange that I can't update simply because I have a
readable copy of it.
Further, from the man page, the only time that getWritableData()
returns NULL is when PFFULX_WRITE_ONCE is PF_ON. In my application,
I have it as PF_OFF (by default, again according to man pages),
but when I call getWritableData(), I keep getting a NULL pointer.
But if I try getCurData() instead, the data returned is the right,
vaild, data. Furhter the getWritableData() is returnig NULL
at only one particular call, other places I call the same
function, returns a pointer to data that I can successfully write
to.
Are there any instances - documented or otherwise - that
the pfFlux::getWritableData() returns NULL?
pfThanks.
Sincerely,
shankar
This archive was generated by hypermail 2.0b2 on Thu Mar 04 1999 - 19:24:19 PST