SEO

I've got the following problem, that I posted to misc@openbsd.org first.

The problem is that if I link an application with pthread, it just won't
read from the sound card. if I don't, it reads fine.

consider the code below. if compiled as:

gcc -o record record.c

it works fine, returns:

$ ./record
4 returned by read

but if compiled:

gcc -o record -pthread record.c

it won't return anything, as it blocks with the call to read.

does anyone have any idea of this fault?


---------8<----------snip here for record.c---------------------
#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <sys/ioctl.h>
#include <errno.h>
#include <sys/audioio.h>

#define FILE_NAME "/dev/audio"
#define SAMPLE_RATE 22050
#define CHANNEL 2
#define BITS_PER_SAMPLE 16
#define BUF_SIZE 4

int main(int argc, char **argv) {
int fd;
audio_info_t audioInfo;
unsigned char buf[BUF_SIZE];
unsigned int len = BUF_SIZE;
ssize_t ret;

fd = open( FILE_NAME, O_RDONLY);

AUDIO_INITINFO( &audioInfo);
audioInfo.record.sample_rate = SAMPLE_RATE;
audioInfo.record.channels = CHANNEL;
audioInfo.record.precision = BITS_PER_SAMPLE;
audioInfo.record.encoding = AUDIO_ENCODING_LINEAR;

if ( ioctl(fd, AUDIO_SETINFO, &audioInfo) ) {
printf("can't set audio info, error: %d\n", errno);
}

ret = read(fd, buf, len);

printf("%d returned by read\n", ret);
if ( ret == -1 ) {
printf("error code %d\n", errno);
}

close(fd);

return 0;
}
--------->8----------snip here for record.c---------------------