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Fix latent portability issue in pgwin32_dispatch_queued_signals().
The first iteration of the signal-checking loop would compute sigmask(0) which expands to 1<<(-1) which is undefined behavior according to the C standard. The lack of field reports of trouble suggest that it evaluates to 0 on all existing Windows compilers, but that's hardly something to rely on. Since signal 0 isn't a queueable signal anyway, we can just make the loop iterate from 1 instead, and save a few cycles as well as avoiding the undefined behavior. In passing, avoid evaluating the volatile expression UNBLOCKED_SIGNAL_QUEUE twice in a row; there's no reason to waste cycles like that. Noted by Aleksander Alekseev, though this isn't his proposed fix. Back-patch to all supported branches.
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@ -33,6 +33,7 @@ HANDLE pgwin32_initial_signal_pipe = INVALID_HANDLE_VALUE;
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*/
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static CRITICAL_SECTION pg_signal_crit_sec;
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/* Note that array elements 0 are unused since they correspond to signal 0 */
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static pqsigfunc pg_signal_array[PG_SIGNAL_COUNT];
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static pqsigfunc pg_signal_defaults[PG_SIGNAL_COUNT];
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@ -105,15 +106,15 @@ pgwin32_signal_initialize(void)
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void
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pgwin32_dispatch_queued_signals(void)
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{
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int i;
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int exec_mask;
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EnterCriticalSection(&pg_signal_crit_sec);
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while (UNBLOCKED_SIGNAL_QUEUE())
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while ((exec_mask = UNBLOCKED_SIGNAL_QUEUE()) != 0)
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{
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/* One or more unblocked signals queued for execution */
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int exec_mask = UNBLOCKED_SIGNAL_QUEUE();
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int i;
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for (i = 0; i < PG_SIGNAL_COUNT; i++)
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for (i = 1; i < PG_SIGNAL_COUNT; i++)
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{
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if (exec_mask & sigmask(i))
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{
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