* lseek(0,...) in snapshot differs from b20.1
@ 1999-09-20 9:43 Paul Berrevoets
1999-09-20 10:12 ` Mumit Khan
1999-09-30 23:42 ` Paul Berrevoets
0 siblings, 2 replies; 4+ messages in thread
From: Paul Berrevoets @ 1999-09-20 9:43 UTC (permalink / raw)
To: cygwin-list
#include <sys/types.h>
#include <unistd.h>
#include <errno.h>
int
main()
{
int rc = lseek(0, (off_t)0, SEEK_CUR);
printf("%d %d\n", rc, rc < 0 ? errno : 0);
return 0;
}
Ouput using b20.1:
0 0
Output using snapshot 1999-09-17:
-1 9
If this change is intentional, could you please explain the rationale?
--
Regards,
Paul Berrevoets
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^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: lseek(0,...) in snapshot differs from b20.1
1999-09-20 9:43 lseek(0,...) in snapshot differs from b20.1 Paul Berrevoets
@ 1999-09-20 10:12 ` Mumit Khan
1999-09-30 23:42 ` Mumit Khan
1999-09-30 23:42 ` Paul Berrevoets
1 sibling, 1 reply; 4+ messages in thread
From: Mumit Khan @ 1999-09-20 10:12 UTC (permalink / raw)
To: Paul Berrevoets; +Cc: cygwin-list
Paul Berrevoets <paul@swi.com> writes:
> #include <sys/types.h>
> #include <unistd.h>
> #include <errno.h>
> int
> main()
> {
> int rc = lseek(0, (off_t)0, SEEK_CUR);
> printf("%d %d\n", rc, rc < 0 ? errno : 0);
> return 0;
> }
>
> Ouput using b20.1:
> 0 0
>
> Output using snapshot 1999-09-17:
> -1 9
>
> If this change is intentional, could you please explain the rationale?
POSIX says something like "Some devices are incapable of seeking and
POSIX does not specify which devices must support it." Linux for example
will set the errno to ESPIPE with your code (which Cygwin should follow
as well instead of using ENODEV); HPUX will return the total number
of total number of bytes written to the descriptor and so on.
Simply put, assuming that stdin is seekable is non-portable and should
be avoided at all costs. I tend to use isatty(), and avoid calling lseek
on a tty device.
Regards,
Mumit
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^ permalink raw reply [flat|nested] 4+ messages in thread
* lseek(0,...) in snapshot differs from b20.1
1999-09-20 9:43 lseek(0,...) in snapshot differs from b20.1 Paul Berrevoets
1999-09-20 10:12 ` Mumit Khan
@ 1999-09-30 23:42 ` Paul Berrevoets
1 sibling, 0 replies; 4+ messages in thread
From: Paul Berrevoets @ 1999-09-30 23:42 UTC (permalink / raw)
To: cygwin-list
#include <sys/types.h>
#include <unistd.h>
#include <errno.h>
int
main()
{
int rc = lseek(0, (off_t)0, SEEK_CUR);
printf("%d %d\n", rc, rc < 0 ? errno : 0);
return 0;
}
Ouput using b20.1:
0 0
Output using snapshot 1999-09-17:
-1 9
If this change is intentional, could you please explain the rationale?
--
Regards,
Paul Berrevoets
--
Want to unsubscribe from this list?
Send a message to cygwin-unsubscribe@sourceware.cygnus.com
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: lseek(0,...) in snapshot differs from b20.1
1999-09-20 10:12 ` Mumit Khan
@ 1999-09-30 23:42 ` Mumit Khan
0 siblings, 0 replies; 4+ messages in thread
From: Mumit Khan @ 1999-09-30 23:42 UTC (permalink / raw)
To: Paul Berrevoets; +Cc: cygwin-list
Paul Berrevoets <paul@swi.com> writes:
> #include <sys/types.h>
> #include <unistd.h>
> #include <errno.h>
> int
> main()
> {
> int rc = lseek(0, (off_t)0, SEEK_CUR);
> printf("%d %d\n", rc, rc < 0 ? errno : 0);
> return 0;
> }
>
> Ouput using b20.1:
> 0 0
>
> Output using snapshot 1999-09-17:
> -1 9
>
> If this change is intentional, could you please explain the rationale?
POSIX says something like "Some devices are incapable of seeking and
POSIX does not specify which devices must support it." Linux for example
will set the errno to ESPIPE with your code (which Cygwin should follow
as well instead of using ENODEV); HPUX will return the total number
of total number of bytes written to the descriptor and so on.
Simply put, assuming that stdin is seekable is non-portable and should
be avoided at all costs. I tend to use isatty(), and avoid calling lseek
on a tty device.
Regards,
Mumit
--
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Send a message to cygwin-unsubscribe@sourceware.cygnus.com
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~1999-09-30 23:42 UTC | newest]
Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
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1999-09-20 9:43 lseek(0,...) in snapshot differs from b20.1 Paul Berrevoets
1999-09-20 10:12 ` Mumit Khan
1999-09-30 23:42 ` Mumit Khan
1999-09-30 23:42 ` Paul Berrevoets
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