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author | William R. Otte <wotte@dre.vanderbilt.edu> | 2006-07-24 15:50:30 +0000 |
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committer | William R. Otte <wotte@dre.vanderbilt.edu> | 2006-07-24 15:50:30 +0000 |
commit | c44379cc7d9c7aa113989237ab0f56db12aa5219 (patch) | |
tree | 66a84b20d47f2269d8bdc6e0323f338763424d3a /ACE/examples/Threads/reader_writer.cpp | |
parent | 3aff90f4a822fcf5d902bbfbcc9fa931d6191a8c (diff) | |
download | ATCD-c44379cc7d9c7aa113989237ab0f56db12aa5219.tar.gz |
Repo restructuring
Diffstat (limited to 'ACE/examples/Threads/reader_writer.cpp')
-rw-r--r-- | ACE/examples/Threads/reader_writer.cpp | 188 |
1 files changed, 188 insertions, 0 deletions
diff --git a/ACE/examples/Threads/reader_writer.cpp b/ACE/examples/Threads/reader_writer.cpp new file mode 100644 index 00000000000..5344ba4d5b4 --- /dev/null +++ b/ACE/examples/Threads/reader_writer.cpp @@ -0,0 +1,188 @@ +// $Id$ + +// This test program verifies the functionality of the ACE_OS +// implementation of readers/writer locks on Win32 and Posix pthreads. + +#include "ace/OS_main.h" +#include "ace/Thread.h" +#include "ace/Thread_Manager.h" +#include "ace/Get_Opt.h" +#include "ace/Atomic_Op.h" + +ACE_RCSID(Threads, reader_writer, "$Id$") + +#if defined (ACE_HAS_THREADS) + +#include "ace/Guard_T.h" +#include "ace/RW_Mutex.h" + +// Default number of iterations. +static int n_iterations = 1000; + +// Default number of loops. +static int n_loops = 100; + +// Default number of readers. +static int n_readers = 6; + +// Default number of writers. +static int n_writers = 2; + +// Thread id of last writer. +static ACE_thread_t shared_thr_id; + +// Lock for shared_thr_id. +static ACE_RW_Mutex rw_mutex; + +// Count of the number of readers and writers. +ACE_Atomic_Op<ACE_Thread_Mutex, int> current_readers, current_writers; + +// Thread manager +static ACE_Thread_Manager thr_mgr; + +// Explain usage and exit. +static void +print_usage_and_die (void) +{ + ACE_DEBUG ((LM_DEBUG, + "usage: %n [-r n_readers] [-w n_writers] [-n iteration_count]\n")); + ACE_OS::exit (1); +} + +// Parse the command-line arguments and set options. +static void +parse_args (int argc, ACE_TCHAR *argv[]) +{ + ACE_Get_Opt get_opt (argc, argv, ACE_TEXT("r:w:n:l:")); + + int c; + + while ((c = get_opt ()) != -1) + switch (c) + { + case 'r': + n_readers = ACE_OS::atoi (get_opt.opt_arg ()); + break; + case 'w': + n_writers = ACE_OS::atoi (get_opt.opt_arg ()); + break; + case 'n': + n_iterations = ACE_OS::atoi (get_opt.opt_arg ()); + break; + case 'l': + n_loops = ACE_OS::atoi (get_opt.opt_arg ()); + break; + default: + print_usage_and_die (); + break; + } +} + +// Iterate <n_iterations> each time checking that nobody modifies the +// data while we have a read lock. + +static void * +reader (void *) +{ + ACE_DEBUG ((LM_DEBUG, "(%t) reader starting\n")); + + for (int iterations = 1; + iterations <= n_iterations; iterations++) + { + ACE_Read_Guard<ACE_RW_Mutex> g(rw_mutex); + + ++current_readers; + + if (current_writers > 0) + ACE_DEBUG ((LM_DEBUG, "(%t) writers found!!!\n")); + + ACE_thread_t thr_id = shared_thr_id; + + for (int loop = 1; loop <= n_loops; loop++) + { + ACE_Thread::yield(); + + if (ACE_OS::thr_equal (shared_thr_id, thr_id) == 0) + ACE_DEBUG ((LM_DEBUG, + "(%t) somebody changed %d to %d\n", + thr_id, shared_thr_id)); + } + + --current_readers; + + ACE_Thread::yield (); + } + return 0; +} + +// Iterate <n_iterations> each time modifying the global data +// and checking that nobody steps on it while we can write it. + +static void * +writer (void *) +{ + ACE_DEBUG ((LM_DEBUG, "(%t) writer starting\n")); + + for (int iterations = 1; + iterations <= n_iterations; + iterations++) + { + ACE_Write_Guard<ACE_RW_Mutex> g(rw_mutex); + + ++current_writers; + + if (current_writers > 1) + ACE_DEBUG ((LM_DEBUG, "(%t) other writers found!!!\n")); + + if (current_readers > 0) + ACE_DEBUG ((LM_DEBUG, "(%t) readers found!!!\n")); + + ACE_thread_t self = ACE_Thread::self (); + shared_thr_id = self; + + for (int loop = 1; loop <= n_loops; loop++) + { + ACE_Thread::yield(); + + if (ACE_OS::thr_equal (shared_thr_id, self) == 0) + ACE_DEBUG ((LM_DEBUG, "(%t) somebody wrote on my data %d\n", + shared_thr_id)); + } + + --current_writers; + + ACE_Thread::yield (); + } + return 0; +} + +// Spawn off threads. + +int ACE_TMAIN (int argc, ACE_TCHAR *argv[]) +{ + ACE_LOG_MSG->open (argv[0]); + parse_args (argc, argv); + + current_readers = 0; // Possibly already done + current_writers = 0; // Possibly already done + + ACE_DEBUG ((LM_DEBUG, "(%t) main thread starting\n")); + + if (thr_mgr.spawn_n (n_readers, (ACE_THR_FUNC) reader, 0, THR_NEW_LWP) == -1 || + thr_mgr.spawn_n (n_writers, (ACE_THR_FUNC) writer, 0, THR_NEW_LWP) == -1) + ACE_ERROR_RETURN ((LM_ERROR, "%p\n", "spawn_n"), 1); + + thr_mgr.wait (); + + ACE_DEBUG ((LM_DEBUG, "(%t) exiting main thread\n")); + return 0; +} + +#else +int +ACE_TMAIN (int, ACE_TCHAR *[]) +{ + ACE_ERROR ((LM_ERROR, "threads not supported on this platform\n")); + return 0; +} +#endif /* ACE_HAS_THREADS */ |