+2020-07-04 Bruno Haible <bruno@clisp.org>
+
+ fatal-signal: Make multithread-safe.
+ * lib/fatal-signal.c (init_fatal_signals): Add comment.
+ (do_init_fatal_signal_set): New function, extracted from
+ init_fatal_signal_set.
+ (fatal_signal_set_once): New variable.
+ (init_fatal_signal_set): Use gl_once.
+
2020-07-03 Bruno Haible <bruno@clisp.org>
getrandom: Fix compilation error on native Windows (regr. 2020-06-28).
static void
init_fatal_signals (void)
{
+ /* This function is multithread-safe even without synchronization, because
+ if two threads execute it simultaneously, the fatal_signals[] array will
+ not change any more after the first of the threads has completed this
+ function. */
static bool fatal_signals_initialized = false;
if (!fatal_signals_initialized)
{
static sigset_t fatal_signal_set;
static void
-init_fatal_signal_set (void)
+do_init_fatal_signal_set (void)
{
- static bool fatal_signal_set_initialized = false;
- if (!fatal_signal_set_initialized)
- {
- size_t i;
+ size_t i;
- init_fatal_signals ();
+ init_fatal_signals ();
- sigemptyset (&fatal_signal_set);
- for (i = 0; i < num_fatal_signals; i++)
- if (fatal_signals[i] >= 0)
- sigaddset (&fatal_signal_set, fatal_signals[i]);
+ sigemptyset (&fatal_signal_set);
+ for (i = 0; i < num_fatal_signals; i++)
+ if (fatal_signals[i] >= 0)
+ sigaddset (&fatal_signal_set, fatal_signals[i]);
+}
- fatal_signal_set_initialized = true;
- }
+/* Ensure that do_init_fatal_signal_set is called once only. */
+gl_once_define(static, fatal_signal_set_once)
+
+static void
+init_fatal_signal_set (void)
+{
+ gl_once (fatal_signal_set_once, do_init_fatal_signal_set);
}
/* Lock and counter that allow block_fatal_signals/unblock_fatal_signals pairs