Hello, kinda stuck here and could use a suggestion.
I am using svgalib to measure vision. Little letters= good vision etc.
The test procedure is to blank the screen, have the speaker go beep, wait one half
second, put up the letter for one second, then blank the screen again. I am calling
sleep() and usleep() fine, but am having trouble making the speaker go "beep". I have
tried using printf("\007"); but there is a BIG latency and it destroys the timing.
I am trying to use ioctl() to generate the tone. However, I am having trouble getting
the file descriptor for the speaker, and not being musically inclined, have no clue as
to what tone I should generate. 500 hertz? 1000 hertz?
Is there a simpler way to sound a beep?????
I always exit, not getting a file descriptor, with the following code:
include <sys/ioctl.h>
include <fcntl.h>
int fd;
if ((fd = open("/dev/audio", O_RDONLY)) < 0){
printf("couldn't get file descriptor for audio device");
exit();
}
ioctl(fd, KDMKTONE, 0x000907ff);
I am using red hat version 6.1 and there are two audio devices
/dev/audio
/dev/audio1
any suggestions would be greatly appreciated.
thanks
joe
--
Joseph M Miller MD University of Arizona
Associate Professor, Ophthalmology and Optical Sciences
655 North Alvernon Way Suite 108
Tucson AZ 85711
Voice 520-321-3677 Fax 520-321-3665 Home 520-742-9849
Primary email: [EMAIL PROTECTED]
Secondary email: [EMAIL PROTECTED]
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