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This restriction does not apply to POSIX applications, as POSIX.1-2008 requires
raise()to be async-signal-safe.
See also undefined behavior 131.
OpenBSD
The OpenBSD signal() manual page lists a few additional functions that are asynchronous-safe in OpenBSD but "probably not on other systems" [OpenBSD], including snprintf(), vsnprintf(), and syslog_r() but only when the syslog_data struct is initialized as a local variable.
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