Messages in this thread | | | Date | Tue, 25 Jun 2002 11:30:52 -0500 | From | Amos Waterland <> | Subject | O_ASYNC question |
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The man page for fcntl() says:
If you set the O_ASYNC status flag on a file descriptor (either by providing this flag with the open(2) call, or by using the F_SETFL command of fcntl), a SIGIO signal is sent whenever input or output becomes possible on that file descriptor.
On a 2.4.18 kernel, this test program waits forever in sigwaitinfo():
#include <fcntl.h> #include <signal.h> #include <stdio.h> #include <stdlib.h> #include <unistd.h>
int main(int argc, char *argv[]) { const int BYTES = 5000000; int i, fd; char buff[BYTES]; char name[] = "/tmp/aio8.XXXXXX"; sigset_t sigset; siginfo_t siginfo;
if ((fd = open(name, O_CREAT|O_WRONLY|O_NONBLOCK|O_ASYNC, 0600)) < 0 || unlink(name)) { perror("creating temp file"); exit(1); }
for (i = 0; i < BYTES; i++) buff[i] = 'Z';
if (sigemptyset(&sigset) || sigaddset(&sigset, SIGIO) || sigprocmask(SIG_BLOCK, &sigset, NULL)) { perror("setting up signal mask"); exit(2); }
if (write(fd, buff, BYTES) < 0) { perror("writing to temp file"); exit(3); }
printf("recv sig: %i\n", sigwaitinfo(&sigset, &siginfo));
return 0; }
Shouldn't SIGIO be raised when the write() completes? (Is O_ASYNC only valid for sockets, maybe?) Thanks in advance.
Amos Waterland - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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