diff options
Diffstat (limited to 'generic/tclClock.c')
| -rw-r--r-- | generic/tclClock.c | 19 |
1 files changed, 18 insertions, 1 deletions
diff --git a/generic/tclClock.c b/generic/tclClock.c index eb52244..7863f84 100644 --- a/generic/tclClock.c +++ b/generic/tclClock.c @@ -2024,10 +2024,27 @@ ClockSecondsObjCmd( static void TzsetIfNecessary(void) { - static char* tzWas = (char *)INT2PTR(-1); /* Previous value of TZ, protected by + static char *tzWas = (char *)INT2PTR(-1); /* Previous value of TZ, protected by * clockMutex. */ + static long tzLastRefresh = 0; /* Used for latency before next refresh */ + static size_t tzEnvEpoch = 0; /* Last env epoch, for faster signaling, + that TZ changed via TCL */ const char *tzIsNow; /* Current value of TZ */ + /* + * Prevent performance regression on some platforms by resolving of system time zone: + * small latency for check whether environment was changed (once per second) + * no latency if environment was changed with tcl-env (compare both epoch values) + */ + Tcl_Time now; + Tcl_GetTime(&now); + if (now.sec == tzLastRefresh && tzEnvEpoch == TclEnvEpoch) { + return; + } + + tzEnvEpoch = TclEnvEpoch; + tzLastRefresh = now.sec; + Tcl_MutexLock(&clockMutex); tzIsNow = getenv("TZ"); if (tzIsNow != NULL && (tzWas == NULL || tzWas == INT2PTR(-1) |