From b63b331d3205fdfcbab8d1eb0b9a72972d5f6d01 Mon Sep 17 00:00:00 2001
From: Ye Luo <yeluo@anl.gov>
Date: Sun, 5 Jul 2020 18:30:25 -0400
Subject: [PATCH] Add safe-guard in fft_parallel.f90

---
 FFTXlib/fft_parallel.f90 | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/FFTXlib/fft_parallel.f90 b/FFTXlib/fft_parallel.f90
index 718f51f71..5eb1449dd 100644
--- a/FFTXlib/fft_parallel.f90
+++ b/FFTXlib/fft_parallel.f90
@@ -257,6 +257,10 @@ CONTAINS
     !
     INTEGER :: comm2s
     !
+#if defined(_OPENMP) && !defined(__FFT_SCALAR_THREAD_SAFE)
+    CALL errore('many_cft3s::execute_using_tasks','needs thread-safe fft_scalar backend selected at compile time.',1)
+#endif
+    !
     IF ( isgn > 0 ) THEN  ! G -> R
 !$omp parallel default(none)                        &
 !$omp          private(i, j, comm2s)                &
@@ -350,6 +354,11 @@ CONTAINS
     ! This implementation requires thread-safe cft_1z
     !
     IMPLICIT NONE
+    !
+#if defined(_OPENMP) && !defined(__FFT_SCALAR_THREAD_SAFE)
+    CALL errore('many_cft3s::execute_using_threads','needs thread-safe fft_scalar backend selected at compile time.',1)
+#endif
+    !
     IF ( isgn > 0 ) THEN  ! G -> R
 !$omp parallel default(none)                                        &
 !$omp          private(i, j)                                        &