Select() function is not working properly in solaris 10.

Question

Hi ,
We are facing an issue with select() in Solaris 10. we had written a sample program to this issue.
Program name :- sel.cpp
int main()
struct timeval sleeptime;
sleeptime.tv_sec = 60;
printf("1\n");
select(0,NULL,NULL,NULL,&sleeptime);
printf("2");
return 0;
When i run this program in Solaris 9, its printing 1 and after one minute its printing 2.
When i run this program on Solaris 10, its printing 1 and 2 without waiting for 60 seconds.
When i tried to print tv_usec, its printing as 0 in solaris 9 and some garbage values in solaris 10.
I think because of that the above select function is not working properly in solaris 10.
Why the tv_usec is not taking 0 as default values in Solaris 10?
We are using our legacy code for past 20 years. So, before going to do any changes we are trying to find why this happenig like this.
Thanks a lot.
Regards,
Srikanth.

Answer 1

haisrig wrote:
Hi ,
We are facing an issue with select() in Solaris 10. we had written a sample program to this issue.
Program name :- sel.cpp
int main()
struct timeval sleeptime;
sleeptime.tv_sec = 60;
printf("1\n");
select(0,NULL,NULL,NULL,&sleeptime);
printf("2");
return 0;
When i run this program in Solaris 9, its printing 1 and after one minute its printing 2.
When i run this program on Solaris 10, its printing 1 and 2 without waiting for 60 seconds.
When i tried to print tv_usec, its printing as 0 in solaris 9 and some garbage values in solaris 10.
I think because of that the above select function is not working properly in solaris 10.
Why the tv_usec is not taking 0 as default values in Solaris 10?
We are using our legacy code for past 20 years. So, before going to do any changes we are trying to find why this happenig like this.Hi
It sounds to me that you've been lucky for 20 years then.
Local POD variables on the stack that aren't explicitly initialized can contain any value. Here's what I see in your app with dbx
(dbx) run
Running: sel
stopped in main at line 9 in file "sel.cpp"
    9      sleeptime.tv_sec = 60;
(dbx) print sleeptime
sleeptime = {
    tv_sec  = -4198732
    tv_usec = 0
}That's on a Solaris 10 SPARC machine. If I try it on a Solaris 10 x86 box then I get
(dbx) print sleeptime
sleeptime = {
tv_sec = -830490588
tv_usec = 134510556
and I see the behaviour that you describe.
Paul