20 files changed, 42 insertions, 143 deletions
diff --git a/ace/OS.h b/ace/OS.h
index 9bd04c9d029..ac8055a1d2e 100644
--- a/ace/OS.h
+++ b/ace/OS.h
@@ -969,12 +969,13 @@ private:
 #   define ACE_DEFAULT_BASE_ADDR ((char *) (64 * 1024 * 1024))
 # endif /* ACE_DEFAULT_BASE_ADDR */
 
+
 // This fudge factor can be overriden for timers that need it, such as on
 // Solaris, by defining the ACE_TIMER_SKEW symbol in the appropriate config
 // header.
-# if !defined (ACE_TIMER_SKEW)
-#   define ACE_TIMER_SKEW 0
-# endif /* ACE_TIMER_SKEW */
+#if !defined (ACE_TIMER_SKEW)
+#  define ACE_TIMER_SKEW 0
+#endif /* ACE_TIMER_SKEW */
 
 // This needs to go here *first* to avoid problems with AIX.
 # if defined (ACE_HAS_PTHREADS)
diff --git a/ace/Timer_Queue_T.h b/ace/Timer_Queue_T.h
index ab665d358ee..9e933b7171a 100644
--- a/ace/Timer_Queue_T.h
+++ b/ace/Timer_Queue_T.h
@@ -288,17 +288,50 @@ public:
 
   /**
    * Get the dispatch information for a timer whose value is <= <cur_time>.
-   * This does not account for <timer_skew>. Returns 1 if there is a
-   * node whose value <= <cur_time> else returns a 0.
+   * This does not account for <timer_skew>. Returns 1 if
+   * there is a node whose value <= <cur_time> else returns a 0.
+   *
    */
   int dispatch_info (const ACE_Time_Value &current_time,
                      ACE_Timer_Node_Dispatch_Info_T<TYPE> &info);
 
   /**
    * Run the <functor> for all timers whose values are <=
-   * <ACE_OS::gettimeofday>.  Also accounts for <timer_skew>.  Returns
-   * the number of timers canceled.
+   * <ACE_OS::gettimeofday>.  Also accounts for <timer_skew>.
+   *
+   * Depending on the resolution of the underlying OS the system calls
+   * like select()/poll() might return at time different than that is
+   * specified in the timeout. Suppose the OS guarantees a resolution of t ms.
+   * The timeline will look like
+   *
+   *             A                   B
+   *             |                   |
+   *             V                   V
+   *  |-------------|-------------|-------------|-------------|
+   *  t             t             t             t             t
+   *
+   *
+   * If you specify a timeout value of A, then the timeout will not occur
+   * at A but at the next interval of the timer, which is later than
+   * that is expected. Similarly, if your timeout value is equal to B,
+   * then the timeout will occur at interval after B. Now depending upon the
+   * resolution of your timeouts and the accuracy of the timeouts
+   * needed for your application, you should set the value of
+   * <timer_skew>. In the above case, if you want the timeout A to fire
+   * no later than A, then you should specify your <timer_skew> to be
+   * A % t.
+   *
+   * The timeout value should be specified via the macro ACE_TIMER_SKEW
+   * in your config.h file. The default value is zero.
+   *
+   * Things get interesting if the t before the timeout value B is zero
+   * i.e your timeout is less than the interval. In that case, you are
+   * almost sure of not getting the desired timeout behaviour. Maybe you
+   * should look for a better OS :-)
+   *
+   *  Returns the number of timers canceled.
    */
+
   /* virtual */ int expire (void);
 
   /**
diff --git a/ace/config-hpux-11.00.h b/ace/config-hpux-11.00.h
index fd28673a939..9d3c9c3a8ba 100644
--- a/ace/config-hpux-11.00.h
+++ b/ace/config-hpux-11.00.h
@@ -57,7 +57,7 @@
 #    define volatile
 
 #else  // aC++ definitions
- 
+
 // Parts of TAO (at least) use __HP_aCC to detect this compiler, but the
 // macro is not set until A.03.13. If it's not set, set it - it won't be an
 // HP-advertised value, but we don't check the value/version - just whether
@@ -321,12 +321,6 @@
 // Platform lacks a typedef for timespec_t, but has struct timespec
 #define ACE_LACKS_TIMESPEC_T
 
-// Platform needs a timer skew value.  It *may* vary by processor, but this
-// one works.  You can override it in your config.h file if needed.
-// It's in units of microseconds.  This value is 10 msec.
-#if !defined (ACE_TIMER_SKEW)
-#  define ACE_TIMER_SKEW 10 * 1000
-#endif /* ACE_TIMER_SKEW */
 
 // Shared library name/path components
 #define ACE_DLL_SUFFIX  ".sl"
diff --git a/ace/config-hpux11.h b/ace/config-hpux11.h
index b449d59a5b1..992b96d1eb5 100644
--- a/ace/config-hpux11.h
+++ b/ace/config-hpux11.h
@@ -158,13 +158,6 @@
 // Platform lacks a typedef for timespec_t, but has struct timespec
 #define ACE_LACKS_TIMESPEC_T
 
-// Platform needs a timer skew value.  It *may* vary by processor, but this
-// one works.  You can override it in your config.h file if needed.
-// It's in units of microseconds.  This value is 10 msec.
-#if !defined (ACE_TIMER_SKEW)
-#  define ACE_TIMER_SKEW 10 * 1000
-#endif /* ACE_TIMER_SKEW */
-
 // Shared library name/path components
 #define ACE_DLL_SUFFIX  ".sl"
 #if defined (__LP64__)
diff --git a/ace/config-irix6.x-common.h b/ace/config-irix6.x-common.h
index 419212687f2..6c01847b8ac 100644
--- a/ace/config-irix6.x-common.h
+++ b/ace/config-irix6.x-common.h
@@ -150,10 +150,6 @@
 
 #define ACE_HAS_GPERF
 
-#if !defined (ACE_TIMER_SKEW)
-# define ACE_TIMER_SKEW 10 * 1000
-#endif /* ACE_TIMER_SKEW */
-
 #define ACE_HAS_NONCONST_SELECT_TIMEVAL
 #define ACE_HAS_BROKEN_DGRAM_SENDV
 
diff --git a/ace/config-linux-common.h b/ace/config-linux-common.h
index ae912abe80d..466294e5640 100644
--- a/ace/config-linux-common.h
+++ b/ace/config-linux-common.h
@@ -263,10 +263,6 @@
 # define ACE_SIZE_T_FORMAT_SPECIFIER ACE_LIB_TEXT ("%lu")
 #endif /* __ia64 */
 
-#if !defined (ACE_TIMER_SKEW)
-# define ACE_TIMER_SKEW 10 * 1000
-#endif /* ACE_TIMER_SKEW */
-
 // Turns off the tracing feature.
 #if !defined (ACE_NTRACE)
 # define ACE_NTRACE 1
diff --git a/ace/config-lynxos.h b/ace/config-lynxos.h
index d64943bc66b..e3282a40d59 100644
--- a/ace/config-lynxos.h
+++ b/ace/config-lynxos.h
@@ -158,11 +158,6 @@
 // on SIG Proactor for this platform.
 // #define ACE_POSIX_SIG_PROACTOR
 
-// Maximum compensation (10 ms) for early return from timed ::select ().
-#if !defined (ACE_TIMER_SKEW)
-# define ACE_TIMER_SKEW 10 * 1000
-#endif /* ACE_TIMER_SKEW */
-
 #define ACE_HAS_BROKEN_PREALLOCATED_OBJECTS_AFTER_FORK 1
 
 // Turns off the tracing feature.
diff --git a/ace/config-osf1-4.0.h b/ace/config-osf1-4.0.h
index 66cb4f9f1ed..7666cf1b3c5 100644
--- a/ace/config-osf1-4.0.h
+++ b/ace/config-osf1-4.0.h
@@ -120,11 +120,6 @@
 # define ACE_LACKS_SYSV_MSQ_PROTOS
 #endif /* _POSIX_C_SOURCE < 199506L */
 
-// Maximum compensation (10 ms) for early return from timed ::select ().
-#if !defined (ACE_TIMER_SKEW)
-# define ACE_TIMER_SKEW 10 * 1000
-#endif /* ACE_TIMER_SKEW */
-
 #define ACE_DEFAULT_BASE_ADDR ((char *) 0x80000000)
 // NOTE: ACE_HAS_64BIT_LONGS is deprecated.  Instead, use ACE_SIZEOF_LONG == 8.
 #define ACE_HAS_64BIT_LONGS
diff --git a/ace/config-pharlap.h b/ace/config-pharlap.h
index d8ebe03341f..374bed01b49 100644
--- a/ace/config-pharlap.h
+++ b/ace/config-pharlap.h
@@ -46,11 +46,6 @@
 // the correct value.
 #define ACE_PAGE_SIZE 4096
 
-// Maximum compensation (10 ms) for early return from timed ::select ().
-#if !defined (ACE_TIMER_SKEW)
-# define ACE_TIMER_SKEW 10 * 1000
-#endif /* ACE_TIMER_SKEW */
-
 // Let the config-win32.h file do its thing
 #undef ACE_CONFIG_H
 #include "ace/config-win32.h"
diff --git a/ace/config-sunos4-g++.h b/ace/config-sunos4-g++.h
index 23924199d72..b1d5f485e00 100644
--- a/ace/config-sunos4-g++.h
+++ b/ace/config-sunos4-g++.h
@@ -20,11 +20,6 @@
 // Maybe it will work?
 #undef ACE_HAS_TEMPLATE_SPECIALIZATION
 
-// Maximum compensation (10 ms) for early return from timed ::select ().
-#if !defined (ACE_TIMER_SKEW)
-# define ACE_TIMER_SKEW 10 * 1000
-#endif /* ACE_TIMER_SKEW */
-
 #define ACE_HAS_HANDLE_SET_OPTIMIZED_FOR_SELECT
 
 #define ACE_LACKS_SYSTIME_H
@@ -92,11 +87,6 @@
 #define ACE_LACKS_DIFFTIME
 #define ACE_HAS_DIRENT
 
-// 10 millisecond fudge factor to account for Solaris timers...
-#if !defined (ACE_TIMER_SKEW)
-#define ACE_TIMER_SKEW 1000 * 10
-#endif /* ACE_TIMER_SKEW */
-
 #define ACE_HAS_SUNOS4_SIGNAL_T
 #define ACE_HAS_CPLUSPLUS_HEADERS
 #if (__GNUC__ > 2 || (__GNUC__ == 2 && __GNUC_MINOR__ > 6))
diff --git a/ace/config-sunos4-lucid3.2.h b/ace/config-sunos4-lucid3.2.h
index fe723d7db6b..e0738e124a8 100644
--- a/ace/config-sunos4-lucid3.2.h
+++ b/ace/config-sunos4-lucid3.2.h
@@ -11,11 +11,6 @@
 #define ACE_LACKS_GETPGID
 #define ACE_LACKS_SETPGID
 
-// Maximum compensation (10 ms) for early return from timed ::select ().
-#if !defined (ACE_TIMER_SKEW)
-# define ACE_TIMER_SKEW 10 * 1000
-#endif /* ACE_TIMER_SKEW */
-
 #define ACE_HAS_HANDLE_SET_OPTIMIZED_FOR_SELECT
 
 #define ACE_HAS_SYS_ERRLIST
@@ -91,11 +86,6 @@
 
 #define ACE_LACKS_DIFFTIME
 
-// 10 millisecond fudge factor to account for Solaris timers...
-#if !defined (ACE_TIMER_SKEW)
-#define ACE_TIMER_SKEW 1000 * 10
-#endif /* ACE_TIMER_SKEW */
-
 // Turns off the tracing feature.
 #if !defined (ACE_NTRACE)
 #define ACE_NTRACE 1
diff --git a/ace/config-sunos4-sun3.x.h b/ace/config-sunos4-sun3.x.h
index 9115692b70b..88acc3e5ded 100644
--- a/ace/config-sunos4-sun3.x.h
+++ b/ace/config-sunos4-sun3.x.h
@@ -9,11 +9,6 @@
 #define ACE_LACKS_GETPGID
 #define ACE_LACKS_SETPGID
 
-// Maximum compensation (10 ms) for early return from timed ::select ().
-#if !defined (ACE_TIMER_SKEW)
-# define ACE_TIMER_SKEW 10 * 1000
-#endif /* ACE_TIMER_SKEW */
-
 #define ACE_HAS_HANDLE_SET_OPTIMIZED_FOR_SELECT
 
 #define ACE_LACKS_POSIX_PROTOTYPES
@@ -84,11 +79,6 @@
 
 #define ACE_LACKS_DIFFTIME
 
-// 10 millisecond fudge factor to account for Solaris timers...
-#if !defined (ACE_TIMER_SKEW)
-#define ACE_TIMER_SKEW 1000 * 10
-#endif /* ACE_TIMER_SKEW */
-
 // Turns off the tracing feature.
 #if !defined (ACE_NTRACE)
 #define ACE_NTRACE 1
diff --git a/ace/config-sunos4-sun4.1.4.h b/ace/config-sunos4-sun4.1.4.h
index 4d070ae887e..54ab33b2aa8 100644
--- a/ace/config-sunos4-sun4.1.4.h
+++ b/ace/config-sunos4-sun4.1.4.h
@@ -13,11 +13,6 @@
 #define ACE_LACKS_SETREGID
 #define ACE_LACKS_SETREUID
 
-// Maximum compensation (10 ms) for early return from timed ::select ().
-#if !defined (ACE_TIMER_SKEW)
-# define ACE_TIMER_SKEW 10 * 1000
-#endif /* ACE_TIMER_SKEW */
-
 #define ACE_HAS_HANDLE_SET_OPTIMIZED_FOR_SELECT
 
 #define ACE_HAS_CHARPTR_SPRINTF
@@ -95,11 +90,6 @@
 
 #define ACE_LACKS_DIFFTIME
 
-// 10 millisecond fudge factor to account for Solaris timers...
-#if !defined (ACE_TIMER_SKEW)
-#define ACE_TIMER_SKEW 1000 * 10
-#endif /* ACE_TIMER_SKEW */
-
 // Turns off the tracing feature.
 #if !defined (ACE_NTRACE)
 #define ACE_NTRACE 1
diff --git a/ace/config-sunos4-sun4.x-orbix.h b/ace/config-sunos4-sun4.x-orbix.h
index 8c5266605b7..98dab1ac8c0 100644
--- a/ace/config-sunos4-sun4.x-orbix.h
+++ b/ace/config-sunos4-sun4.x-orbix.h
@@ -11,11 +11,6 @@
 #define ACE_LACKS_GETPGID
 #define ACE_LACKS_SETPGID
 
-// Maximum compensation (10 ms) for early return from timed ::select ().
-#if !defined (ACE_TIMER_SKEW)
-# define ACE_TIMER_SKEW 10 * 1000
-#endif /* ACE_TIMER_SKEW */
-
 #define ACE_HAS_HANDLE_SET_OPTIMIZED_FOR_SELECT
 
 #define ACE_HAS_CHARPTR_SPRINTF
@@ -94,11 +89,6 @@
 
 #define ACE_LACKS_DIFFTIME
 
-// 10 millisecond fudge factor to account for Solaris timers...
-#if !defined (ACE_TIMER_SKEW)
-#define ACE_TIMER_SKEW 1000 * 10
-#endif /* ACE_TIMER_SKEW */
-
 // Turns off the tracing feature.
 #if !defined (ACE_NTRACE)
 #define ACE_NTRACE 1
diff --git a/ace/config-sunos5.4-centerline-2.x.h b/ace/config-sunos5.4-centerline-2.x.h
index 562dd5ff493..84a685f9153 100644
--- a/ace/config-sunos5.4-centerline-2.x.h
+++ b/ace/config-sunos5.4-centerline-2.x.h
@@ -13,11 +13,6 @@
 // Platform supports pread() and pwrite()
 #define ACE_HAS_P_READ_WRITE
 
-// Maximum compensation (10 ms) for early return from timed ::select ().
-#if !defined (ACE_TIMER_SKEW)
-# define ACE_TIMER_SKEW 10 * 1000
-#endif /* ACE_TIMER_SKEW */
-
 #define ACE_HAS_HANDLE_SET_OPTIMIZED_FOR_SELECT
 
 #define ACE_HAS_XPG4_MULTIBYTE_CHAR
@@ -153,11 +148,6 @@
 
 #define ACE_NEEDS_DEV_IO_CONVERSION
 
-// 10 millisecond fudge factor to account for Solaris timers...
-#if !defined (ACE_TIMER_SKEW)
-# define ACE_TIMER_SKEW 1000 * 10
-#endif /* ACE_TIMER_SKEW */
-
 // Turns off the tracing feature.
 #if !defined (ACE_NTRACE)
 # define ACE_NTRACE 1
diff --git a/ace/config-sunos5.4-g++.h b/ace/config-sunos5.4-g++.h
index 648557989db..3059e3c2aae 100644
--- a/ace/config-sunos5.4-g++.h
+++ b/ace/config-sunos5.4-g++.h
@@ -19,11 +19,6 @@
 #include "ace/config-g++-common.h"
 #define ACE_HAS_GNU_CSTRING_H
 
-// Maximum compensation (10 ms) for early return from timed ::select ().
-#if !defined (ACE_TIMER_SKEW)
-# define ACE_TIMER_SKEW 10 * 1000
-#endif /* ACE_TIMER_SKEW */
-
 #define ACE_HAS_HANDLE_SET_OPTIMIZED_FOR_SELECT
 
 // Platform supports pread() and pwrite()
@@ -171,11 +166,6 @@
 // Use the poll() event demultiplexor rather than select().
 //#define ACE_USE_POLL
 
-// 10 millisecond fudge factor to account for Solaris timers...
-#if !defined (ACE_TIMER_SKEW)
-# define ACE_TIMER_SKEW 1000 * 10
-#endif /* ACE_TIMER_SKEW */
-
 // Turns off the tracing feature.
 #if !defined (ACE_NTRACE)
 # define ACE_NTRACE 1
diff --git a/ace/config-sunos5.4-sunc++-4.x-orbix.h b/ace/config-sunos5.4-sunc++-4.x-orbix.h
index fa44d1521e5..e908543be52 100644
--- a/ace/config-sunos5.4-sunc++-4.x-orbix.h
+++ b/ace/config-sunos5.4-sunc++-4.x-orbix.h
@@ -15,11 +15,6 @@
 
 #define ACE_HAS_TEMPLATE_SPECIALIZATION
 
-// Maximum compensation (10 ms) for early return from timed ::select ().
-#if !defined (ACE_TIMER_SKEW)
-# define ACE_TIMER_SKEW 10 * 1000
-#endif /* ACE_TIMER_SKEW */
-
 #define ACE_HAS_HANDLE_SET_OPTIMIZED_FOR_SELECT
 
 // Platform supports pread() and pwrite()
@@ -179,11 +174,6 @@
 
 #define ACE_NEEDS_DEV_IO_CONVERSION
 
-// 10 millisecond fudge factor to account for Solaris timers...
-#if !defined (ACE_TIMER_SKEW)
-# define ACE_TIMER_SKEW 1000 * 10
-#endif /* ACE_TIMER_SKEW */
-
 // Turns off the tracing feature.
 #if !defined (ACE_NTRACE)
 # define ACE_NTRACE 1
diff --git a/ace/config-sunos5.4-sunc++-4.x.h b/ace/config-sunos5.4-sunc++-4.x.h
index 76392130c56..7e09eb292f3 100644
--- a/ace/config-sunos5.4-sunc++-4.x.h
+++ b/ace/config-sunos5.4-sunc++-4.x.h
@@ -14,11 +14,6 @@
 
 #define ACE_HAS_TEMPLATE_SPECIALIZATION
 
-// Maximum compensation (10 ms) for early return from timed ::select ().
-#if !defined (ACE_TIMER_SKEW)
-# define ACE_TIMER_SKEW 10 * 1000
-#endif /* ACE_TIMER_SKEW */
-
 // Optimize ACE_Handle_Set for select().
 #define ACE_HAS_HANDLE_SET_OPTIMIZED_FOR_SELECT
 
@@ -176,11 +171,6 @@
 
 #define ACE_NEEDS_DEV_IO_CONVERSION
 
-// 10 millisecond fudge factor to account for Solaris timers...
-#if !defined (ACE_TIMER_SKEW)
-# define ACE_TIMER_SKEW 1000 * 10
-#endif /* ACE_TIMER_SKEW */
-
 // Turns off the tracing feature.
 // #define ACE_NTRACE 0
 #if !defined (ACE_NTRACE)
diff --git a/ace/config-sunos5.5.h b/ace/config-sunos5.5.h
index f343a42dc18..005484a9dff 100644
--- a/ace/config-sunos5.5.h
+++ b/ace/config-sunos5.5.h
@@ -149,11 +149,6 @@
 // have link problems with g++ or egcs on SunOS 5.5.
 #define ACE_HAS_REGEX
 
-// Maximum compensation (10 ms) for early return from timed ::select ().
-#if !defined (ACE_TIMER_SKEW)
-# define ACE_TIMER_SKEW 10 * 1000
-#endif /* ACE_TIMER_SKEW */
-
 // Optimize ACE_Handle_Set for select().
 #define ACE_HAS_HANDLE_SET_OPTIMIZED_FOR_SELECT
 
diff --git a/ace/config-tandem.h b/ace/config-tandem.h
index e1a3f96578e..f42b644a56d 100644
--- a/ace/config-tandem.h
+++ b/ace/config-tandem.h
@@ -226,10 +226,6 @@
 //Automatically restart OS system
 // calls when EINTR occurs
 
-// 10 millisecond fudge factor to account for Solaris timers...
-//#if !defined (ACE_TIMER_SKEW)
-//#define ACE_TIMER_SKEW 1000 * 10
-//#endif /* ACE_TIMER_SKEW */
 
 // Platform supports the getrusage() system call.
 //#define ACE_HAS_GETRUSAGE