diff options
| -rw-r--r-- | src/xz/mytime.c | 15 |
1 files changed, 10 insertions, 5 deletions
diff --git a/src/xz/mytime.c b/src/xz/mytime.c index 917eff0f..9eff566f 100644 --- a/src/xz/mytime.c +++ b/src/xz/mytime.c @@ -20,11 +20,16 @@ uint64_t opt_flush_timeout = 0; -// The start_time variable will not represent the actual start time -// if mytime_sigtstp_handler() executes. The signal handler measures -// the amount of time spent stopped and adds it to start_time. -// So, care must be taken in the future if the actual start time needs -// to be displayed for any reason. +// start_time holds the time when the (de)compression was started. +// It's from mytime_now() and thus only useful for calculating relative +// time differences (elapsed time). start_time is initialized by calling +// mytime_set_start_time() and modified by mytime_sigtstp_handler(). +// +// When mytime_sigtstp_handler() is used, start_time is made volatile. +// I'm not sure if that is really required since access to it is guarded +// by signals_block()/signals_unblock() since accessing an uint64_t isn't +// atomic on all systems. But since the variable isn't accessed very +// frequently making it volatile doesn't hurt. #ifdef USE_SIGTSTP_HANDLER static volatile uint64_t start_time; #else |