.TH hal_create_thread "3hal" "2006-10-12" "LinuxCNC Documentation" "HAL"
.SH NAME

hal_create_thread \- Create a HAL thread

.SH SYNTAX
.HP
int hal_create_thread(const char *\fIname\fR, unsigned long \fIperiod\fR, int \fIuses_fp\fR)

.HP
int hal_thread_delete(const char *\fIname\fR)

.SH  ARGUMENTS
.IP \fIname\fR
The name of the thread

.IP \fIperiod\fR
The interval, in nanoseconds, between iterations of the thread

.IP \fIuses_fp\fR
Must be nonzero if a function which uses floating-point will be attached
to this thread.

.SH DESCRIPTION
\fBhal_create_thread\fR establishes a realtime thread that will
execute one or more HAL functions periodically.

All thread periods are rounded to integer multiples of the hardware timer
period, and the timer period is based on the first thread created.  Threads
must be created in order, from the fastest to the slowest.  HAL assigns
decreasing priorities to threads that are created later, so creating them
from fastest to slowest results in rate monotonic priority scheduling.

\fBhal_delete_thread\fR deletes a previously created thread.

.SH REALTIME CONSIDERATIONS
Call only from realtime init code, not from user space or realtime code.

.SH RETURN VALUE
Returns a HAL status code.

.SH SEE ALSO
\fBhal_export_funct(3hal)\fR