rtf_open_sized blocks

Alexander Fedtke ubf at gmx.net
Thu Oct 28 11:58:09 CEST 2004

Btw: rtai-3.1/rtai-testsuite/user/preempt/preempt.c shows the use of
rtf_create() in user/lxrt space! Is this correct?? According the
documentation this must be used in kernel space only...

Why is there a call for rtf_create() AND open() ??

rtf_create(FIFO, 1000);
if ((fifo = open(rtf_getfifobyminor(0,nm,sizeof(nm)), O_RDWR)) < 0) {
   printf("ERROR OPENING FIFO %s\n",nm);

> Hi!
> rtf_open_sized() blocks my lxrt task when the fifo is already opened by a
> plain linux process for blocking read.
> cat /proc/rtai/fifos shows that the linux task has opened the rtf with
> size
> of 1000 bytes allocated by kmalloc (used by 1 resource)
> When starting the lxrt task (that calls rtf_open_sized with size of
> 1.000.000) the fifo resource counter is incremented, but size and
> [k|v]malloc is not changed (lxrt task blocks).
> When killing my lxrt task (by pressing CTRL-C) the fifo recource counter
> will be decremented correctly.
> When restarting my lxrt application everything works fine: resource
> counter
> is incremented, size is adapted and "kmalloc" is replaced by "vmalloc"
> What can I do to get rtf_open_sized() working even on first start of the
> lxrt application.
> BTW: simply starting the linux task after the lxrt task works but is not
> acceptable for my application
> Thanks in advance, Alexander
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