diff --git a/slsDetectorServers/matterhornServer/src/MatterhornApp.cpp b/slsDetectorServers/matterhornServer/src/MatterhornApp.cpp
index 8c37df196..71baa56f8 100644
--- a/slsDetectorServers/matterhornServer/src/MatterhornApp.cpp
+++ b/slsDetectorServers/matterhornServer/src/MatterhornApp.cpp
@@ -1,5 +1,6 @@
 #include "CommandLineOptions.h"
 #include "VirtualMatterhornServer.h"
+#include "sls/thread_utils.h"
 #include "sls/logger.h"
 #include "sls/sls_detector_exceptions.h"
 #include "sls/versionAPI.h"
@@ -10,20 +11,6 @@
 #include <sys/wait.h>
 #include <unistd.h>
 
-// gettid added in glibc 2.30
-#if defined(__APPLE__)
-#include <cstdint>
-#include <pthread.h>
-static inline uint64_t gettid() {
-    uint64_t tid = 0;
-    pthread_threadid_np(nullptr, &tid);
-    return tid;
-}
-#elif __GLIBC__ == 2 && __GLIBC_MINOR__ < 30
-#include <sys/syscall.h>
-#define gettid() syscall(SYS_gettid)
-#endif
-
 using namespace sls;
 
 pid_t pid = -1;
@@ -84,7 +71,7 @@ int main(int argc, char *argv[]) {
                                      // also return EXIT_FAILURE
         }
         LOG(TLogLevel::logINFOBLUE)
-            << "Exiting Stop Server [ Tid: " << gettid() << " ]";
+            << "Exiting Stop Server [ Tid: " << getThreadId() << " ]";
         LOG(sls::logINFO) << "Exiting Stop Server";
     } else if (pid > 0) {
         // parent
@@ -101,7 +88,7 @@ int main(int argc, char *argv[]) {
             }
         } catch (...) {
             LOG(sls::logINFOBLUE)
-                << "Exiting Control Server [ Tid: " << gettid() << " ]";
+                << "Exiting Control Server [ Tid: " << getThreadId() << " ]";
             LOG(sls::logINFO) << "Exiting Detector Server";
             kill(pid, SIGINT);        // tell child to exit
             waitpid(pid, nullptr, 0); // wait for child to exit
@@ -109,7 +96,8 @@ int main(int argc, char *argv[]) {
         }
         waitpid(pid, nullptr, 0); // wait for child to exit
         LOG(sls::logINFOBLUE)
-            << "Exiting Detector Control Server [ Tid: " << gettid() << " ]";
+            << "Exiting Detector Control Server [ Tid: " << getThreadId()
+            << " ]";
         LOG(sls::logINFO) << "Exiting Detector Server";
     } else {
         LOG(sls::logERROR)
diff --git a/slsReceiverSoftware/src/Arping.cpp b/slsReceiverSoftware/src/Arping.cpp
index 7633e041b..28eccfc60 100644
--- a/slsReceiverSoftware/src/Arping.cpp
+++ b/slsReceiverSoftware/src/Arping.cpp
@@ -2,6 +2,7 @@
 // Copyright (C) 2021 Contributors to the SLS Detector Package
 
 #include "Arping.h"
+#include "sls/thread_utils.h"
 
 #include <chrono>
 #include <signal.h>
@@ -11,12 +12,6 @@
 
 namespace sls {
 
-// gettid added in glibc 2.30
-#if __GLIBC__ == 2 && __GLIBC_MINOR__ < 30
-#include <sys/syscall.h>
-#define gettid() syscall(SYS_gettid)
-#endif
-
 void func(int signum) { wait(NULL); }
 
 Arping::Arping() {}
@@ -59,7 +54,7 @@ void Arping::StartProcess() {
     childPid = fork();
     // child process
     if (childPid == 0) {
-        LOG(logINFOBLUE) << "Created [ Arping Process, Tid: " << gettid()
+        LOG(logINFOBLUE) << "Created [ Arping Process, Tid: " << getThreadId()
                          << " ]";
         ProcessExecution();
     }
diff --git a/slsReceiverSoftware/src/ClientInterface.cpp b/slsReceiverSoftware/src/ClientInterface.cpp
index 0c08534a8..3cfc9d6fe 100644
--- a/slsReceiverSoftware/src/ClientInterface.cpp
+++ b/slsReceiverSoftware/src/ClientInterface.cpp
@@ -3,6 +3,7 @@
 #include "ClientInterface.h"
 #include "sls/ServerSocket.h"
 #include "sls/StaticVector.h"
+#include "sls/thread_utils.h"
 #include "sls/ToString.h"
 
 #include "sls/sls_detector_exceptions.h"
@@ -27,12 +28,6 @@ namespace sls {
 using ns = std::chrono::nanoseconds;
 using Interface = ServerInterface;
 
-// gettid added in glibc 2.30
-#if __GLIBC__ == 2 && __GLIBC_MINOR__ < 30
-#include <sys/syscall.h>
-#define gettid() syscall(SYS_gettid)
-#endif
-
 std::mutex ClientInterface::callbackMutex;
 
 ClientInterface::~ClientInterface() {
@@ -47,7 +42,7 @@ ClientInterface::ClientInterface(uint16_t portNumber)
     : detType(GENERIC), portNumber(portNumber), server(portNumber) {
     validatePortNumber(portNumber);
     functionTable();
-    parentThreadId = gettid();
+    parentThreadId = getThreadId();
     tcpThread =
         make_unique<std::thread>(&ClientInterface::startTCPServer, this);
 }
@@ -79,7 +74,7 @@ void ClientInterface::registerCallBackRawDataReady(
 }
 
 void ClientInterface::startTCPServer() {
-    tcpThreadId = gettid();
+    tcpThreadId = getThreadId();
     LOG(logINFOBLUE) << "Created [ TCP server Tid: " << tcpThreadId << "]";
     LOG(logINFO) << "SLS Receiver starting TCP Server on port " << portNumber
                  << '\n';
diff --git a/slsReceiverSoftware/src/FrameSynchronizerApp.cpp b/slsReceiverSoftware/src/FrameSynchronizerApp.cpp
index fc48814a9..349674294 100644
--- a/slsReceiverSoftware/src/FrameSynchronizerApp.cpp
+++ b/slsReceiverSoftware/src/FrameSynchronizerApp.cpp
@@ -7,6 +7,7 @@
  */
 #include "CommandLineOptions.h"
 #include "sls/Receiver.h"
+#include "sls/thread_utils.h"
 #include "sls/ToString.h"
 #include "sls/container_utils.h"
 #include "sls/logger.h"
@@ -31,12 +32,6 @@
 std::vector<std::thread> threads;
 sls::TLogLevel printHeadersLevel = sls::logDEBUG;
 
-// gettid added in glibc 2.30
-#if __GLIBC__ == 2 && __GLIBC_MINOR__ < 30
-#include <sys/syscall.h>
-#define gettid() syscall(SYS_gettid)
-#endif
-
 /** Define Colors to print data call back in different colors for different
  * recievers */
 #define PRINT_IN_COLOR(c, f, ...)                                              \
@@ -522,7 +517,8 @@ int main(int argc, char *argv[]) {
         return EXIT_SUCCESS;
     }
 
-    LOG(sls::logINFOBLUE) << "Current Process [ Tid: " << gettid() << ']';
+    LOG(sls::logINFOBLUE) << "Current Process [ Tid: " << sls::getThreadId()
+                          << ']';
 
     // close files on ctrl+c
     sls::setupSignalHandler(SIGINT, sigInterruptHandler);
@@ -548,8 +544,8 @@ int main(int argc, char *argv[]) {
         sem_t *semaphore = &semaphores[i];
         threads.emplace_back(
             [i, semaphore, port, user_data, &threadException]() {
-                LOG(sls::logINFOBLUE)
-                    << "Thread " << i << " [ Tid: " << gettid() << ']';
+                LOG(sls::logINFOBLUE) << "Thread " << i << " [ Tid: "
+                                      << sls::getThreadId() << ']';
                 try {
                     sls::Receiver receiver(port);
                     receiver.registerCallBackStartAcquisition(
@@ -567,8 +563,8 @@ int main(int argc, char *argv[]) {
                     threadException = std::current_exception();
                     raise(SIGINT);
                 }
-                LOG(sls::logINFOBLUE)
-                    << "Exiting Thread " << i << " [ Tid: " << gettid() << " ]";
+                LOG(sls::logINFOBLUE) << "Exiting Thread " << i << " [ Tid: "
+                                      << sls::getThreadId() << " ]";
             });
     }
 
diff --git a/slsReceiverSoftware/src/MultiReceiverApp.cpp b/slsReceiverSoftware/src/MultiReceiverApp.cpp
index a1bc4cb83..ad6b869ca 100644
--- a/slsReceiverSoftware/src/MultiReceiverApp.cpp
+++ b/slsReceiverSoftware/src/MultiReceiverApp.cpp
@@ -4,6 +4,7 @@
  * binary */
 #include "CommandLineOptions.h"
 #include "sls/Receiver.h"
+#include "sls/thread_utils.h"
 #include "sls/ToString.h"
 #include "sls/container_utils.h"
 #include "sls/logger.h"
@@ -16,12 +17,6 @@
 #include <sys/wait.h> //wait
 #include <unistd.h>
 
-// gettid added in glibc 2.30
-#if __GLIBC__ == 2 && __GLIBC_MINOR__ < 30
-#include <sys/syscall.h>
-#define gettid() syscall(SYS_gettid)
-#endif
-
 /** Define Colors to print data call back in different colors for different
  * recievers */
 #define PRINT_IN_COLOR(c, f, ...)                                              \
@@ -156,7 +151,8 @@ int main(int argc, char *argv[]) {
         return EXIT_SUCCESS;
     }
 
-    LOG(sls::logINFOBLUE) << "Current Process [ Tid: " << gettid() << ']';
+    LOG(sls::logINFOBLUE) << "Current Process [ Tid: " << sls::getThreadId()
+                          << ']';
 
     // close files on ctrl+c
     sls::setupSignalHandler(SIGINT, sigInterruptHandler);
@@ -182,7 +178,8 @@ int main(int argc, char *argv[]) {
         /**	- if child process */
         else if (pid == 0) {
             LOG(sls::logINFOBLUE)
-                << "Child process " << i << " [ Tid: " << gettid() << ']';
+                << "Child process " << i << " [ Tid: " << sls::getThreadId()
+                << ']';
 
             try {
                 uint16_t port = m.port + i;
@@ -213,13 +210,13 @@ int main(int argc, char *argv[]) {
                 // each child process gets a copy of the semaphore
                 sem_wait(&semaphore);
                 sem_destroy(&semaphore);
-                LOG(sls::logINFOBLUE)
-                    << "Exiting Child Process [ Tid: " << gettid() << ']';
+                LOG(sls::logINFOBLUE) << "Exiting Child Process [ Tid: "
+                                      << sls::getThreadId() << ']';
                 exit(EXIT_SUCCESS);
             } catch (...) {
                 sem_destroy(&semaphore);
-                LOG(sls::logINFOBLUE)
-                    << "Exiting Child Process [ Tid: " << gettid() << " ]";
+                LOG(sls::logINFOBLUE) << "Exiting Child Process [ Tid: "
+                                      << sls::getThreadId() << " ]";
                 exit(EXIT_FAILURE);
             }
         }
diff --git a/slsReceiverSoftware/src/Receiver.cpp b/slsReceiverSoftware/src/Receiver.cpp
index c9a299b19..f7372ba0e 100644
--- a/slsReceiverSoftware/src/Receiver.cpp
+++ b/slsReceiverSoftware/src/Receiver.cpp
@@ -19,12 +19,6 @@
 
 namespace sls {
 
-// gettid added in glibc 2.30
-#if __GLIBC__ == 2 && __GLIBC_MINOR__ < 30
-#include <sys/syscall.h>
-#define gettid() syscall(SYS_gettid)
-#endif
-
 Receiver::~Receiver() = default;
 
 Receiver::Receiver(uint16_t port) {
diff --git a/slsReceiverSoftware/src/ReceiverApp.cpp b/slsReceiverSoftware/src/ReceiverApp.cpp
index 92ff84b50..b6d38689d 100644
--- a/slsReceiverSoftware/src/ReceiverApp.cpp
+++ b/slsReceiverSoftware/src/ReceiverApp.cpp
@@ -3,6 +3,7 @@
 /* slsReceiver */
 #include "CommandLineOptions.h"
 #include "sls/Receiver.h"
+#include "sls/thread_utils.h"
 #include "sls/ToString.h"
 #include "sls/container_utils.h"
 #include "sls/logger.h"
@@ -13,12 +14,6 @@
 #include <semaphore.h>
 #include <unistd.h>
 
-// gettid added in glibc 2.30
-#if __GLIBC__ == 2 && __GLIBC_MINOR__ < 30
-#include <sys/syscall.h>
-#define gettid() syscall(SYS_gettid)
-#endif
-
 sem_t semaphore;
 
 /**
@@ -44,7 +39,8 @@ int main(int argc, char *argv[]) {
         return EXIT_SUCCESS;
     }
 
-    LOG(sls::logINFOBLUE) << "Current Process [ Tid: " << gettid() << " ]";
+    LOG(sls::logINFOBLUE) << "Current Process [ Tid: " << sls::getThreadId()
+                          << " ]";
 
     // close files on ctrl+c
     sls::setupSignalHandler(SIGINT, sigInterruptHandler);
@@ -60,10 +56,11 @@ int main(int argc, char *argv[]) {
         sem_destroy(&semaphore);
     } catch (...) {
         sem_destroy(&semaphore);
-        LOG(sls::logINFOBLUE) << "Exiting [ Tid: " << gettid() << " ]";
+        LOG(sls::logINFOBLUE)
+            << "Exiting [ Tid: " << sls::getThreadId() << " ]";
         throw;
     }
-    LOG(sls::logINFOBLUE) << "Exiting [ Tid: " << gettid() << " ]";
+    LOG(sls::logINFOBLUE) << "Exiting [ Tid: " << sls::getThreadId() << " ]";
     LOG(sls::logINFO) << "Exiting Receiver";
     return EXIT_SUCCESS;
 }
diff --git a/slsReceiverSoftware/src/ThreadObject.cpp b/slsReceiverSoftware/src/ThreadObject.cpp
index 183b31ece..eec0d2aaf 100644
--- a/slsReceiverSoftware/src/ThreadObject.cpp
+++ b/slsReceiverSoftware/src/ThreadObject.cpp
@@ -6,18 +6,13 @@
  ***********************************************/
 
 #include "ThreadObject.h"
+#include "sls/thread_utils.h"
 #include "sls/container_utils.h"
 #include <iostream>
 #include <unistd.h>
 
 namespace sls {
 
-// gettid added in glibc 2.30
-#if __GLIBC__ == 2 && __GLIBC_MINOR__ < 30
-#include <sys/syscall.h>
-#define gettid() syscall(SYS_gettid)
-#endif
-
 ThreadObject::ThreadObject(int index, std::string type)
     : index(index), type(type) {
     LOG(logDEBUG) << type << " thread created: " << index;
@@ -46,7 +41,7 @@ void ThreadObject::StartRunning() { runningFlag = true; }
 void ThreadObject::StopRunning() { runningFlag = false; }
 
 void ThreadObject::RunningThread() {
-    threadId = gettid();
+    threadId = getThreadId();
     LOG(logINFOBLUE) << "Created [ " << type << "Thread " << index
                      << ", Tid: " << threadId << "]";
     while (!killThread) {
diff --git a/slsSupportLib/include/sls/thread_utils.h b/slsSupportLib/include/sls/thread_utils.h
new file mode 100644
index 000000000..c1a7ff69c
--- /dev/null
+++ b/slsSupportLib/include/sls/thread_utils.h
@@ -0,0 +1,49 @@
+// SPDX-License-Identifier: LGPL-3.0-or-other
+// Copyright (C) 2021 Contributors to the SLS Detector Package
+#pragma once
+
+/**
+ * @file thread_utils.h
+ * @short Portable per-thread identifier for diagnostics/logging.
+ *
+ * Returns a unique-within-process thread id of the calling thread:
+ *   - Linux, glibc >= 2.30: the system gettid() (pid_t).
+ *   - Linux, glibc <  2.30: syscall(SYS_gettid) (long, cast to pid_t).
+ *   - macOS:                pthread_threadid_np() (uint64_t, truncated to pid_t).
+ *
+ * The macOS kernel thread id is 64-bit. To stay drop-in compatible with the
+ * existing call sites that store the result in pid_t (e.g. ThreadObject::
+ * threadId, ClientInterface::parentThreadId / tcpThreadId), we truncate to
+ * pid_t. The value is used for diagnostics only and is still unique enough
+ * within a single process.
+ */
+
+#include <sys/types.h> // pid_t
+
+#if defined(__APPLE__)
+#include <cstdint>
+#include <pthread.h>
+#elif defined(__linux__)
+#include <unistd.h>
+#if !defined(__GLIBC__) ||                                                     \
+    !(__GLIBC__ > 2 || (__GLIBC__ == 2 && __GLIBC_MINOR__ >= 30))
+#include <sys/syscall.h>
+#endif
+#endif
+
+namespace sls {
+
+inline pid_t getThreadId() noexcept {
+#if defined(__APPLE__)
+    std::uint64_t tid = 0;
+    pthread_threadid_np(nullptr, &tid);
+    return static_cast<pid_t>(tid);
+#elif defined(__GLIBC__) &&                                                    \
+    (__GLIBC__ > 2 || (__GLIBC__ == 2 && __GLIBC_MINOR__ >= 30))
+    return ::gettid();
+#else
+    return static_cast<pid_t>(::syscall(SYS_gettid));
+#endif
+}
+
+} // namespace sls