[gcc(refs/users/aoliva/heads/testme)] libstdc++: testsuite: tolerate non-cancelling sleep

[Alexandre Oliva <aoliva@gcc.gnu.org>]

https://gcc.gnu.org/g:f6c91261915c2395a97e75e44279a5531b0d7a45

commit f6c91261915c2395a97e75e44279a5531b0d7a45
Author: Alexandre Oliva <oliva@adacore.com>
Date:   Mon Jun 20 20:44:07 2022 -0300

    libstdc++: testsuite: tolerate non-cancelling sleep
    
    Though sleep, nanosleep and clock_nanosleep are all POSIX cancellation
    points, not all target systems follow this POSIX requirement.
    30_threads/thread/native_handle/cancel.cc will run until it times out
    on such systems.
    
    Rather than failing a C++ library test because of a limitation of the
    target system, this patch gives the test a chance to successfully
    exercise the features it intends to exercise, by introducing a
    cancellation point in a loop that would otherwise run indefinitely on
    systems exhibiting this limitation.
    
    
    for  libstdc++-v3/ChangeLog
    
            * testsuite/30_threads/thread/native_handle/cancel.cc: Add an
            explicit cancellation point in case sleep_for lacks one.

Diff:
---
 libstdc++-v3/testsuite/30_threads/thread/native_handle/cancel.cc | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/libstdc++-v3/testsuite/30_threads/thread/native_handle/cancel.cc b/libstdc++-v3/testsuite/30_threads/thread/native_handle/cancel.cc
index dca162b3ace..3cef97e8c53 100644
--- a/libstdc++-v3/testsuite/30_threads/thread/native_handle/cancel.cc
+++ b/libstdc++-v3/testsuite/30_threads/thread/native_handle/cancel.cc
@@ -30,7 +30,11 @@ void f(std::atomic<bool>& started)
 {
   started = true;
   while (true)
-    std::this_thread::sleep_for(std::chrono::milliseconds(100));
+    {
+      std::this_thread::sleep_for(std::chrono::milliseconds(100));
+      // In case the target system doesn't make sleep a cancellation point...
+      pthread_testcancel();
+    }
 }
 
 int main()