diff --git a/CMakeLists.txt b/CMakeLists.txt
index fead70c..f05ae92 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -68,6 +68,7 @@ IF (USE_PTHREADS)
     FIND_PACKAGE(pthreads REQUIRED)
     INCLUDE_DIRECTORIES(${PTHREADS_INCLUDE_DIR})
     ADD_DEFINITIONS(-D_REENTRANT)
+    set(PTHREADS_LIBRARY PThreads4W::PThreads4W)
 ENDIF()
 
 # Math library (not available in MSVC or MINGW)
diff --git a/fitsio2.h b/fitsio2.h
index 1adb17b..19f8511 100644
--- a/fitsio2.h
+++ b/fitsio2.h
@@ -26,7 +26,7 @@ extern int Fitsio_Pthread_Status;
 #define FFUNLOCK1(lockname) (Fitsio_Pthread_Status = pthread_mutex_unlock(&lockname))
 #define FFLOCK   FFLOCK1(Fitsio_Lock)
 #define FFUNLOCK FFUNLOCK1(Fitsio_Lock)
-#define ffstrtok(str, tok, save) strtok_r(str, tok, save)
+#define ffstrtok(str, tok, save) strtok_s(str, tok, save)
 
 #else
 #define FFLOCK