--- boost/interprocess/detail/os_thread_functions.hpp	2026-08-06 01:09:10.000000000 +0800
+++ boost/interprocess/detail/os_thread_functions.hpp	2026-08-14 18:53:43.000000000 +0800
@@ -62,6 +62,13 @@
    #include <pthread_np.h>
 #elif defined(__APPLE__)
    #include <pthread.h>
+   // pthread_threadid_np needs a 10.6+ deployment target and is never exported
+   // for PowerPC, where Libc's arch guards exclude it from libSystem even on 10.6
+   #if !defined(__POWERPC__) && \
+       (!defined(__ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__) || \
+         __ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__ >= 1060)
+      #define BOOST_INTERPROCESS_APPLE_HAS_PTHREAD_THREADID_NP
+   #endif
 #elif defined(__NetBSD__)
    #include <lwp.h>
 #elif defined(__OpenBSD__)
@@ -324,7 +331,8 @@
 inline OS_systemwide_thread_id_t get_invalid_systemwide_thread_id()
 {  return -1;   }
 
-#elif defined(__APPLE__) && !defined(BOOST_INTERPROCESS_USE_PTHREAD_AS_SYSTEMWIDE_THREAD_ID)
+#elif defined(__APPLE__) && defined(BOOST_INTERPROCESS_APPLE_HAS_PTHREAD_THREADID_NP) && \
+      !defined(BOOST_INTERPROCESS_USE_PTHREAD_AS_SYSTEMWIDE_THREAD_ID)
 
 typedef uint64_t OS_systemwide_thread_id_t;