You only have to prevent the usage of new C++11 keywords like auto, lambda, initializer lists, override, ... Include boost header instead of std header.

For examples have a look at my demo C++ test code.

TCOV=1 make
# ...

make ctest
cd build && ctest -C debug
Test project /Users/clausklein/Workspace/cpp/Threadpool/build
      Start  1: async_server
 1/24 Test  #1: async_server .....................   Passed    0.01 sec
      Start  2: chrono_io_ex1
 2/24 Test  #2: chrono_io_ex1 ....................   Passed    0.01 sec
      Start  3: daytime_client
 3/24 Test  #3: daytime_client ...................   Passed    0.01 sec
      Start  4: default_executor
 4/24 Test  #4: default_executor .................   Passed    1.01 sec
      Start  5: executor
 5/24 Test  #5: executor .........................   Passed    6.99 sec
      Start  6: lockfree_spsc_queue
 6/24 Test  #6: lockfree_spsc_queue ..............   Passed    1.26 sec
      Start  7: make_future
 7/24 Test  #7: make_future ......................   Passed    0.04 sec
      Start  8: multi_thread_pass
 8/24 Test  #8: multi_thread_pass ................   Passed    0.02 sec
      Start  9: perf_shared_mutex
 9/24 Test  #9: perf_shared_mutex ................   Passed    3.34 sec
      Start 10: serial_executor
10/24 Test #10: serial_executor ..................   Passed    2.01 sec
      Start 11: shared_monitor
11/24 Test #11: shared_monitor ...................   Passed    9.16 sec
      Start 12: shared_mutex
12/24 Test #12: shared_mutex .....................   Passed   13.01 sec
      Start 13: shared_ptr
13/24 Test #13: shared_ptr .......................   Passed    0.01 sec
      Start 14: stopwatch_reporter_example
14/24 Test #14: stopwatch_reporter_example .......   Passed    0.01 sec
      Start 15: strict_lock
15/24 Test #15: strict_lock ......................   Passed    0.01 sec
      Start 16: synchronized_person
16/24 Test #16: synchronized_person ..............   Passed    0.01 sec
      Start 17: test_atomic_counter
17/24 Test #17: test_atomic_counter ..............   Passed    0.62 sec
      Start 18: test_shared_mutex
18/24 Test #18: test_shared_mutex ................   Passed    9.04 sec
      Start 19: thread_pool
19/24 Test #19: thread_pool ......................   Passed    0.01 sec
      Start 20: thread_tss_test
20/24 Test #20: thread_tss_test ..................   Passed    0.01 sec
      Start 21: trylock_test
21/24 Test #21: trylock_test .....................   Passed    0.63 sec
      Start 22: user_scheduler
22/24 Test #22: user_scheduler ...................   Passed    0.01 sec
      Start 23: volatile
23/24 Test #23: volatile .........................   Passed    0.01 sec
      Start 24: test_threads
24/24 Test #24: test_threads .....................   Passed    4.20 sec

100% tests passed, 0 tests failed out of 24

Total Test time (real) =  51.49 sec
Claus-MBP:Threadpool clausklein$

There exist a generic lock algorithm

see https://en.cppreference.com/w/cpp/thread/lock

and https://en.cppreference.com/w/cpp/named_req/Lockable

Boost provides a version of this function that takes a sequence of Lockable objects defined by a pair of iterators. std::scoped_lock offers a RAII wrapper for this function, and is generally preferred to a naked call to std::lock.

• https://www.boost.org/doc/libs/1_68_0/doc/html/thread/synchronization.html#thread.synchronization.lock_functions.lock_range

std::condition_variable_any can be used with std::shared_lock in order to wait on a std::shared_mutex in shared ownership mode. A possible use for std::condition_variable_any with custom Lockable types is to provide convenient interruptible waits: the custom lock operation would both lock the associated mutex as expected, and also perform the necessary setup to notify this condition variable when the interrupting signal is received.

• https://en.cppreference.com/w/cpp/thread/condition_variable
• https://en.cppreference.com/w/cpp/thread/condition_variable_any/wait

• 1. Williams (2012), "C++ concurrency in action" 9.2.4 Interrupting a wait on std::condition_variable_any
• http:https://think-async.com/Asio/Documentation
• https://en.cppreference.com/w/cpp/language/raii
• https://en.cppreference.com/w/cpp/memory/enable_shared_from_this