From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <1215525959.487374472c1bc@domain.hid> Date: Tue, 08 Jul 2008 16:05:59 +0200 From: nourry@domain.hid MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Subject: [Xenomai-help] rt_read_timer value List-Id: Help regarding installation and common use of Xenomai List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: xenomai@xenomai.org Hi, i try to make a little program that just records time reaction : a pictur= e appears and we must press a key. Time between image appeared and keypress= is recorded. For that, i use rt_time_read() in aperiodic mode (since if we don't speci= fy rt_task_set_periodic(), aperiodic mode is default, that's right ?). It seems working until a little bit more 2 seconds, but after that, value returned is negative and decreasing, while it was positive and increasing= (weird because i've read that in aperiodic mode it should be decreasing all the = time). Moreover, i believe remember that while beginning this program, time was = always decreasing, like real-time task were affected by the rest of the program. I must record time until 5 seconds after image appeared, and this problem doesn't ease the task. I must have made a mistake, can someone help me ? Another little question, which functions, librairies, calls in one word c= an we make in real-time tasks without breaking it ? I want to use event detecti= on from SDL library to catch keypress, there's a function that polls for events (= for the moment i use kbhit). It doesn't seems to increase latency in an endless l= oop. I must keep latency under 1 ms since goal is to measure time reaction with accuracy. Thanks to all, Antoine