diff --git a/demos/api/get_data_perf.cpp b/demos/api/get_data_perf.cpp
index 5f46e56c49dfc7071a2072dad90acdbb10d143d6..766e8a45331aa4833a3c65805ddef4c65ee8bfe3 100644
--- a/demos/api/get_data_perf.cpp
+++ b/demos/api/get_data_perf.cpp
@@ -15,7 +15,7 @@ int main(int argc, char **argv)
 
   // create a post-processing dataset
   gmsh::plugin::setNumber("NewView", "Value", 1.234);
-  gmsh::plugin::run("NewView");
+  int t = gmsh::plugin::run("NewView");
 
   // retrieve the dataset as a vector of vectors (one per tag)
   std::string type;
@@ -24,13 +24,13 @@ int main(int argc, char **argv)
   double time;
   int numComp;
   std::cout << "before get" << std::endl;
-  gmsh::view::getModelData(0, 0, type, tags, data, time, numComp);
+  gmsh::view::getModelData(t, 0, type, tags, data, time, numComp);
   std::cout << "after get" << std::endl;
 
   // retrieve the dataset as a single vector
   std::vector<double> data2;
   std::cout << "before getHomogeneous" << std::endl;
-  gmsh::view::getHomogeneousModelData(0, 0, type, tags, data2, time, numComp);
+  gmsh::view::getHomogeneousModelData(t, 0, type, tags, data2, time, numComp);
   std::cout << "after getHomogeneous" << std::endl;
 
   gmsh::finalize();
diff --git a/demos/api/get_data_perf.py b/demos/api/get_data_perf.py
index c3c96a172a076828c5ca6ca9aec7d5aa01b42386..4a91fc9a2d4db017e600b0253cf643245cc63877 100644
--- a/demos/api/get_data_perf.py
+++ b/demos/api/get_data_perf.py
@@ -13,16 +13,16 @@ gmsh.model.mesh.generate(2)
 
 # create a post-processing dataset
 gmsh.plugin.setNumber("NewView", "Value", 1.234)
-gmsh.plugin.run("NewView")
+t = gmsh.plugin.run("NewView")
 
 # retrieve the dataset as a vector of vectors (one for each tag)
 print("before get")
-type, tags, data, time, numComp = gmsh.view.getModelData(0, 0)
+type, tags, data, time, numComp = gmsh.view.getModelData(t, 0)
 print("after get")
 
 # retrieve the dataset as a single vector (muuuuch faster for Python)
 print("before getHomogeneous")
-type2, tags2, data2, time2, numComp2 = gmsh.view.getHomogeneousModelData(0, 0)
+type2, tags2, data2, time2, numComp2 = gmsh.view.getHomogeneousModelData(t, 0)
 print("after getHomogeneous")
 
 gmsh.finalize()
diff --git a/demos/api/volume.py b/demos/api/volume.py
index 3e2c88d9901c22648a42fce8a6a9438405c29b77..27f816b5999488f01a47c9c30f5d20f4c753ffb6 100644
--- a/demos/api/volume.py
+++ b/demos/api/volume.py
@@ -14,9 +14,9 @@ gmsh.model.mesh.generate(2)
 
 gmsh.plugin.setNumber("MeshVolume", "Dimension", 2)
 gmsh.plugin.setNumber("MeshVolume", "PhysicalGroup", p)
-gmsh.plugin.run("MeshVolume")
+t = gmsh.plugin.run("MeshVolume")
 
-_, _, data = gmsh.view.getListData(0)
+_, _, data = gmsh.view.getListData(t)
 print("volume from mesh = ", data[0][3])
 
 gmsh.finalize()