From e06e966e10b4edb27f9813ddffc34529abd4bb91 Mon Sep 17 00:00:00 2001
From: Fred Hornsey <fred@hornsey.us>
Date: Thu, 11 Apr 2019 23:43:06 -0500
Subject: Add ACE_OS::thr_gettid()

---
 ACE/ace/OS_NS_Thread.cpp | 13 +++++++++++++
 ACE/ace/OS_NS_Thread.h   | 18 ++++++++++++++++++
 ACE/ace/OS_NS_Thread.inl | 11 ++++++++++-
 ACE/ace/config-linux.h   |  4 ++++
 4 files changed, 45 insertions(+), 1 deletion(-)

diff --git a/ACE/ace/OS_NS_Thread.cpp b/ACE/ace/OS_NS_Thread.cpp
index 8a052271775..315713a35a4 100644
--- a/ACE/ace/OS_NS_Thread.cpp
+++ b/ACE/ace/OS_NS_Thread.cpp
@@ -17,6 +17,7 @@
 #include "ace/Thread_Mutex.h"
 #include "ace/Condition_Thread_Mutex.h"
 #include "ace/Guard_T.h"
+#include "ace/OS_NS_sys_resource.h"
 
 extern "C" void
 ACE_MUTEX_LOCK_CLEANUP_ADAPTER_NAME (void *args)
@@ -4806,6 +4807,18 @@ ACE_OS::unique_name (const void *object,
 }
 #endif
 
+#ifdef ACE_HAS_GETTID
+pid_t
+ACE_OS::thr_gettid ()
+{
+#  ifdef ACE_LINUX
+  return syscall (SYS_gettid);
+#  else
+#    error "No implementation for thr_gettid(), please disable ACE_HAS_GETTID"
+#  endif
+}
+#endif
+
 ACE_END_VERSIONED_NAMESPACE_DECL
 
 #if defined (ACE_VXWORKS) && !defined (__RTP__)
diff --git a/ACE/ace/OS_NS_Thread.h b/ACE/ace/OS_NS_Thread.h
index f932a701cea..061351c2dcd 100644
--- a/ACE/ace/OS_NS_Thread.h
+++ b/ACE/ace/OS_NS_Thread.h
@@ -1754,6 +1754,24 @@ namespace ACE_OS {
   ACE_NAMESPACE_INLINE_FUNCTION
   ssize_t thr_id (char buffer[], size_t buffer_length);
 
+#ifdef ACE_HAS_GETTID
+  /**
+   * Wrapper for pid_t gettid(). For systems that support it (only Linux as of
+   * writing), get the system-wide thread id (TID) for the current thread.
+   *
+   * These are similar to PIDs and, on x86 Linux at least, are much shorter
+   * than the what is returned from thr_id(), which is represents a address.
+   */
+  pid_t thr_gettid ();
+
+  /**
+   * Puts the string representation of pid_t thr_gettid() into the buffer and
+   * returns number of bytes added.
+   */
+  ACE_NAMESPACE_INLINE_FUNCTION
+  ssize_t thr_gettid (char buffer[], size_t buffer_length);
+#endif
+
   /// State is THR_CANCEL_ENABLE or THR_CANCEL_DISABLE
   ACE_NAMESPACE_INLINE_FUNCTION
   int thr_setcancelstate (int new_state, int *old_state);
diff --git a/ACE/ace/OS_NS_Thread.inl b/ACE/ace/OS_NS_Thread.inl
index d4023d05704..53866dde742 100644
--- a/ACE/ace/OS_NS_Thread.inl
+++ b/ACE/ace/OS_NS_Thread.inl
@@ -3178,12 +3178,21 @@ ACE_OS::thr_id (char buffer[], size_t buffer_length)
 #else /* ACE_HAS_OPAQUE_PTHREAD_T */
   return ACE_OS::snprintf (buffer,
                            buffer_length,
-                           "%lu",
+                           "%lx",
                            (unsigned long) t_id);
 #endif /* ACE_HAS_OPAQUE_PTHREAD_T */
 #endif /* WIN32 */
 }
 
+#ifdef ACE_HAS_GETTID
+ACE_INLINE ssize_t
+ACE_OS::thr_gettid (char buffer[], size_t buffer_length)
+{
+  return ACE_OS::snprintf (buffer, buffer_length, "%u",
+    static_cast<unsigned> (ACE_OS::thr_gettid()));
+}
+#endif
+
 ACE_INLINE ACE_thread_t
 ACE_OS::thr_self (void)
 {
diff --git a/ACE/ace/config-linux.h b/ACE/ace/config-linux.h
index e248aea30b3..cb11f84ae63 100644
--- a/ACE/ace/config-linux.h
+++ b/ACE/ace/config-linux.h
@@ -449,6 +449,10 @@
 
 #endif /* __UCLIBC__ */
 
+#if (LINUX_VERSION_CODE >= KERNEL_VERSION (2,4,11))
+#  define ACE_HAS_GETTID // See ACE_OS::thr_gettid()
+#endif
+
 #include /**/ "ace/post.h"
 
 #endif /* ACE_CONFIG_LINUX_H */
-- 
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