5 files changed, 12 insertions, 0 deletions
diff --git a/htdp.f b/htdp.f
index 5f0e024..8786e11 100644
--- a/htdp.f
+++ b/htdp.f
@@ -25,6 +25,10 @@ C  You must change HTDP version and date here, if necessary
 
       HTDP_version = '3.5.0'
       Version_date = 'November 29, 2022'
+      call linkbd     ! require linker to include block data
+      call linkeq     ! require linker to include block data
+      call linkps     ! require linker to include block data
+      call linkvl     ! require linker to include block data
 
 *** Introduce variables for file IDs
 
diff --git a/initbd.f b/initbd.f
index da4775c..1492726 100644
--- a/initbd.f
+++ b/initbd.f
@@ -1,3 +1,5 @@
+      subroutine linkbd ! require linker to include block data
+      end subroutine
       BLOCK DATA INITBD
 
 *  Initializes velocity grid polygon boundaries.
diff --git a/initeq.f b/initeq.f
index b209a7e..530c292 100644
--- a/initeq.f
+++ b/initeq.f
@@ -1,3 +1,5 @@
+      subroutine linkeq ! require linker to include block data
+      end subroutine
       BLOCK DATA INITEQ
       
 *  Initializes co-seismic earthquake models for HTDP executable.
diff --git a/initps.f b/initps.f
index 155e7a2..f162646 100644
--- a/initps.f
+++ b/initps.f
@@ -1,3 +1,5 @@
+      subroutine linkps ! require linker to include block data
+      end subroutine
       BLOCK DATA INITPS
       IMPLICIT DOUBLE PRECISION (A-H, O-Z)
       IMPLICIT INTEGER*4 (I-N)
diff --git a/initvl.f b/initvl.f
index 50310b6..16854a3 100644
--- a/initvl.f
+++ b/initvl.f
@@ -1,3 +1,5 @@
+      subroutine linkvl ! require linker to include block data
+      end subroutine
       BLOCK DATA INITVL
       IMPLICIT DOUBLE PRECISION (A-H, O-Z)
       IMPLICIT INTEGER*4 (I-N)