diff --git a/modules/libcom/src/osi/epicsThread.cpp b/modules/libcom/src/osi/epicsThread.cpp
index 892d73de0..372806edb 100644
--- a/modules/libcom/src/osi/epicsThread.cpp
+++ b/modules/libcom/src/osi/epicsThread.cpp
@@ -31,6 +31,17 @@
 
 using namespace std;
 
+epicsThreadId epicsShareAPI epicsThreadCreate (
+    const char * name, unsigned int priority, unsigned int stackSize,
+    EPICSTHREADFUNC funptr,void * parm )
+{
+    epicsThreadOpts opts;
+    opts.priority = priority;
+    opts.stackSize = stackSize;
+
+    return epicsThreadCreateOpt(name, funptr, parm, &opts);
+}
+
 epicsThreadRunable::~epicsThreadRunable () {}
 void epicsThreadRunable::run () {}
 void epicsThreadRunable::show ( unsigned int ) const {}
diff --git a/modules/libcom/src/osi/epicsThread.h b/modules/libcom/src/osi/epicsThread.h
index 84b2c4788..d0879a8eb 100644
--- a/modules/libcom/src/osi/epicsThread.h
+++ b/modules/libcom/src/osi/epicsThread.h
@@ -65,6 +65,22 @@ epicsShareFunc void epicsThreadRealtimeLock(void);
 
 epicsShareFunc void epicsShareAPI epicsThreadExitMain(void);
 
+typedef struct epicsThreadOpts {
+    /** Thread priority in OSI range (cf. epicsThreadPriority*) */
+    unsigned int priority;
+    /** Thread stack size, as returned by epicsThreadGetStackSize().
+     *
+     * @warning Do not pass enum epicsThreadStackSizeClass directly!
+     */
+    unsigned int stackSize;
+} epicsThreadOpts;
+
+epicsShareFunc void epicsThreadOptsDefaults(epicsThreadOpts *opts);
+
+epicsShareFunc epicsThreadId epicsThreadCreateOpt (
+    const char * name,
+    EPICSTHREADFUNC funptr, void * parm,
+    const epicsThreadOpts *opts );
 epicsShareFunc epicsThreadId epicsShareAPI epicsThreadCreate (
     const char * name, unsigned int priority, unsigned int stackSize,
     EPICSTHREADFUNC funptr,void * parm );
diff --git a/modules/libcom/src/osi/os/RTEMS/osdThread.c b/modules/libcom/src/osi/os/RTEMS/osdThread.c
index 769e95820..7b478df65 100644
--- a/modules/libcom/src/osi/os/RTEMS/osdThread.c
+++ b/modules/libcom/src/osi/os/RTEMS/osdThread.c
@@ -148,6 +148,13 @@ epicsThreadGetStackSize (epicsThreadStackSizeClass size)
     return stackSize;
 }
 
+static const epicsThreadOpts opts_default = {epicsThreadPriorityLow, 5000};
+
+void epicsThreadOptsDefaults(epicsThreadOpts *opts)
+{
+    *opts = opts_default;
+}
+
 /*
  * Ensure integrity of task variable list
  */
@@ -263,13 +270,17 @@ void epicsThreadRealtimeLock(void)
  * Create and start a new thread
  */
 epicsThreadId
-epicsThreadCreate (const char *name,
-    unsigned int priority, unsigned int stackSize,
-    EPICSTHREADFUNC funptr,void *parm)
+epicsThreadCreateOpt (
+    const char * name,
+    EPICSTHREADFUNC funptr, void * parm, const epicsThreadOpts *opts )
 {
     rtems_id tid;
     rtems_status_code sc;
     char c[4];
+    unsigned stackSize;
+
+    if(!opts) opts = &opts_default;
+    stackSize = opts->stackSize;
 
     if (!initialized) epicsThreadInit();
     if (stackSize < RTEMS_MINIMUM_STACK_SIZE) {
@@ -279,7 +290,7 @@ epicsThreadCreate (const char *name,
     }
     strncpy (c, name, sizeof c);
     sc = rtems_task_create (rtems_build_name (c[0], c[1], c[2], c[3]),
-         epicsThreadGetOssPriorityValue (priority),
+         epicsThreadGetOssPriorityValue (opts->priority),
          stackSize,
          RTEMS_PREEMPT|RTEMS_NO_TIMESLICE|RTEMS_NO_ASR|RTEMS_INTERRUPT_LEVEL(0),
          RTEMS_FLOATING_POINT|RTEMS_LOCAL,
diff --git a/modules/libcom/src/osi/os/WIN32/osdThread.c b/modules/libcom/src/osi/os/WIN32/osdThread.c
index 8cdb4a3f4..f78c7c0f4 100644
--- a/modules/libcom/src/osi/os/WIN32/osdThread.c
+++ b/modules/libcom/src/osi/os/WIN32/osdThread.c
@@ -464,6 +464,13 @@ epicsShareFunc unsigned int epicsShareAPI
     return stackSizeTable[stackSizeClass];
 }
 
+static const epicsThreadOpts opts_default = {epicsThreadPriorityLow, STACK_SIZE(1)};
+
+void epicsThreadOptsDefaults(epicsThreadOpts *opts)
+{
+    *opts = opts_default;
+}
+
 void epicsThreadCleanupWIN32 ()
 {
     win32ThreadGlobal * pGbl = fetchWin32ThreadGlobal ();
@@ -579,8 +586,10 @@ static win32ThreadParam * epicsThreadImplicitCreate ( void )
 /*
  * epicsThreadCreate ()
  */
-epicsShareFunc epicsThreadId epicsShareAPI epicsThreadCreate (const char *pName,
-    unsigned int priority, unsigned int stackSize, EPICSTHREADFUNC pFunc,void *pParm)
+epicsThreadId epicsThreadCreateOpt (
+    const char * pName,
+    EPICSTHREADFUNC pFunc, void * pParm,
+    const epicsThreadOpts *opts )
 {
     win32ThreadGlobal * pGbl = fetchWin32ThreadGlobal ();
     win32ThreadParam * pParmWIN32;
@@ -592,18 +601,20 @@ epicsShareFunc epicsThreadId epicsShareAPI epicsThreadCreate (const char *pName,
         return NULL;
     }
 
+    if(!opts) opts = &opts_default;
+
     pParmWIN32 = epicsThreadParmCreate ( pName );
     if ( pParmWIN32 == 0 ) {
         return ( epicsThreadId ) pParmWIN32;
     }
     pParmWIN32->funptr = pFunc;
     pParmWIN32->parm = pParm;
-    pParmWIN32->epicsPriority = priority;
+    pParmWIN32->epicsPriority = opts->priority;
 
     {
         unsigned threadId;
         pParmWIN32->handle = (HANDLE) _beginthreadex ( 
-            0, stackSize, epicsWin32ThreadEntry, 
+            0, opts->stackSize, epicsWin32ThreadEntry,
             pParmWIN32, 
             CREATE_SUSPENDED | STACK_SIZE_PARAM_IS_A_RESERVATION, 
             & threadId );
@@ -615,7 +626,7 @@ epicsShareFunc epicsThreadId epicsShareAPI epicsThreadCreate (const char *pName,
         pParmWIN32->id = ( DWORD ) threadId ;
     }
 
-    osdPriority = epicsThreadGetOsdPriorityValue (priority);
+    osdPriority = epicsThreadGetOsdPriorityValue (opts->priority);
     bstat = SetThreadPriority ( pParmWIN32->handle, osdPriority );
     if (!bstat) {
         CloseHandle ( pParmWIN32->handle ); 
diff --git a/modules/libcom/src/osi/os/posix/osdThread.c b/modules/libcom/src/osi/os/posix/osdThread.c
index 755390eed..65e1929ec 100644
--- a/modules/libcom/src/osi/os/posix/osdThread.c
+++ b/modules/libcom/src/osi/os/posix/osdThread.c
@@ -430,15 +430,22 @@ void epicsThreadRealtimeLock(void)
 #endif
 }
 
-epicsShareFunc unsigned int epicsShareAPI epicsThreadGetStackSize (epicsThreadStackSizeClass stackSizeClass)
-{
 #if defined (OSITHREAD_USE_DEFAULT_STACK)
-    return 0;
+#define STACK_SIZE(f) (0)
 #elif defined(_POSIX_THREAD_ATTR_STACKSIZE) && _POSIX_THREAD_ATTR_STACKSIZE > 0
     #define STACK_SIZE(f) (f * 0x10000 * sizeof(void *))
     static const unsigned stackSizeTable[epicsThreadStackBig+1] = {
         STACK_SIZE(1), STACK_SIZE(2), STACK_SIZE(4)
     };
+#else
+#define STACK_SIZE(f) (0)
+#endif /*_POSIX_THREAD_ATTR_STACKSIZE*/
+
+epicsShareFunc unsigned int epicsShareAPI epicsThreadGetStackSize (epicsThreadStackSizeClass stackSizeClass)
+{
+#if defined (OSITHREAD_USE_DEFAULT_STACK)
+    return 0;
+#elif defined(_POSIX_THREAD_ATTR_STACKSIZE) && _POSIX_THREAD_ATTR_STACKSIZE > 0
     if (stackSizeClass<epicsThreadStackSmall) {
         errlogPrintf("epicsThreadGetStackSize illegal argument (too small)");
         return stackSizeTable[epicsThreadStackBig];
@@ -454,6 +461,13 @@ epicsShareFunc unsigned int epicsShareAPI epicsThreadGetStackSize (epicsThreadSt
     return 0;
 #endif /*_POSIX_THREAD_ATTR_STACKSIZE*/
 }
+
+static const epicsThreadOpts opts_default = {epicsThreadPriorityLow, STACK_SIZE(1)};
+
+void epicsThreadOptsDefaults(epicsThreadOpts *opts)
+{
+    *opts = opts_default;
+}
 
 epicsShareFunc void epicsShareAPI epicsThreadOnce(epicsThreadOnceId *id, void (*func)(void *), void *arg)
 {
@@ -496,19 +510,22 @@ epicsShareFunc void epicsShareAPI epicsThreadOnce(epicsThreadOnceId *id, void (*
     checkStatusQuit(status,"pthread_mutex_unlock","epicsThreadOnce");
 }
 
-epicsShareFunc epicsThreadId epicsShareAPI epicsThreadCreate(const char *name,
-    unsigned int priority, unsigned int stackSize,
-    EPICSTHREADFUNC funptr,void *parm)
+epicsThreadId
+epicsThreadCreateOpt (
+    const char * name,
+    EPICSTHREADFUNC funptr, void * parm, const epicsThreadOpts *opts )
 {
     epicsThreadOSD *pthreadInfo;
     int status;
     sigset_t blockAllSig, oldSig;
 
+    if(!opts) opts = &opts_default;
+
     epicsThreadInit();
     assert(pcommonAttr);
     sigfillset(&blockAllSig);
     pthread_sigmask(SIG_SETMASK,&blockAllSig,&oldSig);
-    pthreadInfo = init_threadInfo(name,priority,stackSize,funptr,parm);
+    pthreadInfo = init_threadInfo(name,opts->priority,opts->stackSize,funptr,parm);
     if(pthreadInfo==0) return 0;
     pthreadInfo->isEpicsThread = 1;
     setSchedulingPolicy(pthreadInfo,SCHED_FIFO);
@@ -518,7 +535,7 @@ epicsShareFunc epicsThreadId epicsShareAPI epicsThreadCreate(const char *name,
     if(status==EPERM){
         /* Try again without SCHED_FIFO*/
         free_threadInfo(pthreadInfo);
-        pthreadInfo = init_threadInfo(name,priority,stackSize,funptr,parm);
+        pthreadInfo = init_threadInfo(name,opts->priority,opts->stackSize,funptr,parm);
         if(pthreadInfo==0) return 0;
         pthreadInfo->isEpicsThread = 1;
         status = pthread_create(&pthreadInfo->tid,&pthreadInfo->attr,
diff --git a/modules/libcom/src/osi/os/vxWorks/osdThread.c b/modules/libcom/src/osi/os/vxWorks/osdThread.c
index ce01ea609..6a71301a2 100644
--- a/modules/libcom/src/osi/os/vxWorks/osdThread.c
+++ b/modules/libcom/src/osi/os/vxWorks/osdThread.c
@@ -133,6 +133,13 @@ unsigned int epicsThreadGetStackSize (epicsThreadStackSizeClass stackSizeClass)
     return stackSizeTable[stackSizeClass];
 }
 
+static const epicsThreadOpts opts_default = {epicsThreadPriorityLow, 4000*ARCH_STACK_FACTOR};
+
+void epicsThreadOptsDefaults(epicsThreadOpts *opts)
+{
+    *opts = opts_default;
+}
+
 struct epicsThreadOSD {};
     /* Strictly speaking this should be a WIND_TCB, but we only need it to
      * be able to create an epicsThreadId that is guaranteed never to be
@@ -190,19 +197,22 @@ static void createFunction(EPICSTHREADFUNC func, void *parm)
 #else
   #define TASK_FLAGS (VX_FP_TASK)
 #endif
-epicsThreadId epicsThreadCreate(const char *name,
-    unsigned int priority, unsigned int stackSize,
-    EPICSTHREADFUNC funptr,void *parm)
+epicsThreadId
+epicsThreadCreateOpt (
+    const char * name,
+    EPICSTHREADFUNC funptr, void * parm, const epicsThreadOpts *opts )
 {
     int tid;
 
+    if(!opts) opts = &opts_default;
+
     epicsThreadInit();
-    if(stackSize<100) {
-        errlogPrintf("epicsThreadCreate %s illegal stackSize %d\n",name,stackSize);
+    if(opts->stackSize<100) {
+        errlogPrintf("epicsThreadCreate %s illegal stackSize %d\n",name,opts->stackSize);
         return(0);
     }
-    tid = taskSpawn((char *)name,getOssPriorityValue(priority),
-        TASK_FLAGS, stackSize,
+    tid = taskSpawn((char *)name,getOssPriorityValue(opts->priority),
+        TASK_FLAGS, opts->stackSize,
         (FUNCPTR)createFunction,(int)funptr,(int)parm,
         0,0,0,0,0,0,0,0);
     if(tid==ERROR) {