* [Patch, fortran] PR 42434 Update documentation for SYSTEM_CLOCK
@ 2011-02-05 20:04 Janne Blomqvist
2011-02-05 20:13 ` Steve Kargl
0 siblings, 1 reply; 3+ messages in thread
From: Janne Blomqvist @ 2011-02-05 20:04 UTC (permalink / raw)
To: GCC Patches, Fortran List
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Hi,
the attached patch updates the documentation to match the
implementation of SYSTEM_CLOCK, where we now provide access to a
high-resolution monotonic clock via clock_gettime().
Tested with make pdf, Ok for trunk?
2011-02-05 Janne Blomqvist <jb@gcc.gnu.org>
PR fortran/42434
* intrinsic.texi (SYSTEM_CLOCK): Update documentation.
--
Janne Blomqvist
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diff --git a/gcc/fortran/intrinsic.texi b/gcc/fortran/intrinsic.texi
index d8a97c5..f0287f6 100644
--- a/gcc/fortran/intrinsic.texi
+++ b/gcc/fortran/intrinsic.texi
@@ -11812,14 +11812,29 @@ and should considered in new code for future portability.
@table @asis
@item @emph{Description}:
-Determines the @var{COUNT} of milliseconds of wall clock time since
-the Epoch (00:00:00 UTC, January 1, 1970) modulo @var{COUNT_MAX},
-@var{COUNT_RATE} determines the number of clock ticks per second.
-@var{COUNT_RATE} and @var{COUNT_MAX} are constant and specific to
-@command{gfortran}.
+Determines the @var{COUNT} of a processor clock since an unspecified
+time in the past modulo @var{COUNT_MAX}, @var{COUNT_RATE} determines
+the number of clock ticks per second. If the platform supports a high
+resolution monotonic clock, that clock is used and can provide up to
+nanosecond resolution. If a high resolution monotonic clock is not
+available, the implementation falls back to a potentially lower
+resolution realtime clock.
+
+@var{COUNT_RATE} and @var{COUNT_MAX} vary depending on the kind of the
+arguments. For @var{kind=8} arguments, @var{COUNT} represents
+nanoseconds, and for @var{kind=4} arguments, @var{COUNT} represents
+milliseconds. Other than the kind dependency, @var{COUNT_RATE} and
+@var{COUNT_MAX} are constant, however the particular values are
+specific to @command{gfortran}.
If there is no clock, @var{COUNT} is set to @code{-HUGE(COUNT)}, and
-@var{COUNT_RATE} and @var{COUNT_MAX} are set to zero
+@var{COUNT_RATE} and @var{COUNT_MAX} are set to zero.
+
+When running on a platform using the GNU C library (glibc), or a
+derivative thereof, the high resolution monotonic clock is available
+only when linking with the @var{rt} library. This can be done
+explicitly by adding the @code{-lrt} flag when linking the
+application, but is also done implicitly when using OpenMP.
@item @emph{Standard}:
Fortran 95 and later
@@ -11832,11 +11847,11 @@ Subroutine
@item @emph{Arguments}:
@multitable @columnfractions .15 .70
-@item @var{COUNT} @tab (Optional) shall be a scalar of type default
+@item @var{COUNT} @tab (Optional) shall be a scalar of type
@code{INTEGER} with @code{INTENT(OUT)}.
-@item @var{COUNT_RATE} @tab (Optional) shall be a scalar of type default
+@item @var{COUNT_RATE} @tab (Optional) shall be a scalar of type
@code{INTEGER} with @code{INTENT(OUT)}.
-@item @var{COUNT_MAX} @tab (Optional) shall be a scalar of type default
+@item @var{COUNT_MAX} @tab (Optional) shall be a scalar of type
@code{INTEGER} with @code{INTENT(OUT)}.
@end multitable
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [Patch, fortran] PR 42434 Update documentation for SYSTEM_CLOCK
2011-02-05 20:04 [Patch, fortran] PR 42434 Update documentation for SYSTEM_CLOCK Janne Blomqvist
@ 2011-02-05 20:13 ` Steve Kargl
2011-02-05 20:21 ` Janne Blomqvist
0 siblings, 1 reply; 3+ messages in thread
From: Steve Kargl @ 2011-02-05 20:13 UTC (permalink / raw)
To: Janne Blomqvist; +Cc: GCC Patches, Fortran List
On Sat, Feb 05, 2011 at 10:03:50PM +0200, Janne Blomqvist wrote:
> Hi,
>
> the attached patch updates the documentation to match the
> implementation of SYSTEM_CLOCK, where we now provide access to a
> high-resolution monotonic clock via clock_gettime().
>
> Tested with make pdf, Ok for trunk?
>
> 2011-02-05 Janne Blomqvist <jb@gcc.gnu.org>
>
> PR fortran/42434
> * intrinsic.texi (SYSTEM_CLOCK): Update documentation.
>
OK.
--
Steve
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [Patch, fortran] PR 42434 Update documentation for SYSTEM_CLOCK
2011-02-05 20:13 ` Steve Kargl
@ 2011-02-05 20:21 ` Janne Blomqvist
0 siblings, 0 replies; 3+ messages in thread
From: Janne Blomqvist @ 2011-02-05 20:21 UTC (permalink / raw)
To: Steve Kargl; +Cc: GCC Patches, Fortran List
On Sat, Feb 5, 2011 at 22:13, Steve Kargl
<sgk@troutmask.apl.washington.edu> wrote:
> On Sat, Feb 05, 2011 at 10:03:50PM +0200, Janne Blomqvist wrote:
>> Hi,
>>
>> the attached patch updates the documentation to match the
>> implementation of SYSTEM_CLOCK, where we now provide access to a
>> high-resolution monotonic clock via clock_gettime().
>>
>> Tested with make pdf, Ok for trunk?
>>
>> 2011-02-05 Janne Blomqvist <jb@gcc.gnu.org>
>>
>> PR fortran/42434
>> * intrinsic.texi (SYSTEM_CLOCK): Update documentation.
>>
>
> OK.
>
> --
> Steve
>
Thanks for the quick review,
Sending fortran/ChangeLog
Sending fortran/intrinsic.texi
Transmitting file data ..
Committed revision 169854.
--
Janne Blomqvist
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