diff --git a/src/jl_exported_funcs.inc b/src/jl_exported_funcs.inc
index cba609be50c5f..ac004cda653b7 100644
--- a/src/jl_exported_funcs.inc
+++ b/src/jl_exported_funcs.inc
@@ -103,6 +103,7 @@
     XX(jl_copy_ast) \
     XX(jl_copy_code_info) \
     XX(jl_cpu_threads) \
+    XX(jl_effective_threads) \
     XX(jl_crc32c_sw) \
     XX(jl_create_system_image) \
     XX(jl_cstr_to_string) \
diff --git a/src/julia.h b/src/julia.h
index 863e9c8de7cbb..4b5948583bf9c 100644
--- a/src/julia.h
+++ b/src/julia.h
@@ -1635,6 +1635,7 @@ JL_DLLEXPORT int jl_errno(void) JL_NOTSAFEPOINT;
 JL_DLLEXPORT void jl_set_errno(int e) JL_NOTSAFEPOINT;
 JL_DLLEXPORT int32_t jl_stat(const char *path, char *statbuf) JL_NOTSAFEPOINT;
 JL_DLLEXPORT int jl_cpu_threads(void) JL_NOTSAFEPOINT;
+JL_DLLEXPORT int jl_effective_threads(void) JL_NOTSAFEPOINT;
 JL_DLLEXPORT long jl_getpagesize(void) JL_NOTSAFEPOINT;
 JL_DLLEXPORT long jl_getallocationgranularity(void) JL_NOTSAFEPOINT;
 JL_DLLEXPORT int jl_is_debugbuild(void) JL_NOTSAFEPOINT;
diff --git a/src/sys.c b/src/sys.c
index 8f2be76e648c8..ffd43b36d4f68 100644
--- a/src/sys.c
+++ b/src/sys.c
@@ -436,7 +436,7 @@ JL_DLLEXPORT int jl_cpu_threads(void) JL_NOTSAFEPOINT
 #endif
 }
 
-int jl_effective_threads(void) JL_NOTSAFEPOINT
+JL_DLLEXPORT int jl_effective_threads(void) JL_NOTSAFEPOINT
 {
     int cpu = jl_cpu_threads();
     int masksize = uv_cpumask_size();
diff --git a/test/cmdlineargs.jl b/test/cmdlineargs.jl
index 8d58672d30f09..e16573bfbe70a 100644
--- a/test/cmdlineargs.jl
+++ b/test/cmdlineargs.jl
@@ -218,7 +218,7 @@ let exename = `$(Base.julia_cmd()) --startup-file=no --color=no`
 
     # -t, --threads
     code = "print(Threads.nthreads())"
-    cpu_threads = ccall(:jl_cpu_threads, Int32, ())
+    cpu_threads = ccall(:jl_effective_threads, Int32, ())
     @test string(cpu_threads) ==
           read(`$exename --threads auto -e $code`, String) ==
           read(`$exename --threads=auto -e $code`, String) ==