Warning: main(/www/www/htdocs/style/globals.php) [function.main]: failed to open stream: No such file or directory in /www/www/docs/6.4.1/neutrino/lib_ref/n/nanospin_count.html on line 1
Warning: main() [function.include]: Failed opening '/www/www/htdocs/style/globals.php' for inclusion (include_path='.:/www/www/common:/www/www/php/lib/php') in /www/www/docs/6.4.1/neutrino/lib_ref/n/nanospin_count.html on line 1
Warning: main(/www/www/htdocs/style/header.php) [function.main]: failed to open stream: No such file or directory in /www/www/docs/6.4.1/neutrino/lib_ref/n/nanospin_count.html on line 8
Warning: main() [function.include]: Failed opening '/www/www/htdocs/style/header.php' for inclusion (include_path='.:/www/www/common:/www/www/php/lib/php') in /www/www/docs/6.4.1/neutrino/lib_ref/n/nanospin_count.html on line 8
Busy-wait without blocking for a number of iterations
#include <time.h>
void nanospin_count( unsigned long count );
- count
- The number of iterations that you want to busy-wait for.
libc
Use the -l c option to
qcc
to link against this library.
This library is usually included automatically.
The nanospin_count() function busy-waits for the number of
iterations specified in count. Use
nanospin_ns_to_count()
to turn a number of nanoseconds
into an iteration count suitable for nanospin_count().
|
The nanospin*() functions are designed for use with
hardware that requires short time delays between accesses.
You should use them to delay only for times less than a few milliseconds.
For longer delays, use the POSIX
timer_*()
functions. |
Busy-wait for at least 100 nanoseconds:
#include <time.h>
#include <sys/syspage.h>
unsigned long time = 100;
…
/* Wake up the hardware, then wait for it to be ready. */
nanospin_count( nanospin_ns_to_count( time ) );
/* Use the hardware. */
…
QNX Neutrino
Safety: | |
Cancellation point |
No |
Interrupt handler |
Yes |
Signal handler |
Yes |
Thread |
Yes |
You should use busy-waiting only when absolutely necessary for
accessing hardware.
nanosleep(),
nanospin(),
nanospin_calibrate(),
nanospin_ns(),
nanospin_ns_to_count(),
sched_yield(),
sleep(),
timer_create()
Warning: main(/www/www/htdocs/style/footer.php) [function.main]: failed to open stream: No such file or directory in /www/www/docs/6.4.1/neutrino/lib_ref/n/nanospin_count.html on line 155
Warning: main() [function.include]: Failed opening '/www/www/htdocs/style/footer.php' for inclusion (include_path='.:/www/www/common:/www/www/php/lib/php') in /www/www/docs/6.4.1/neutrino/lib_ref/n/nanospin_count.html on line 155