nicely handle argc/argv (gmshInitialize) in python

Common/gmsh.i

 %module gmsh
+
+// "int &outTag" in function arguments is replaced by an append of outTag to the
+// value returned by the function
 %include typemaps.i
-// reference to int is appended to the returned values of the function
 %apply int &OUTPUT { int &outTag };
+
+// handle gracefully the arguments of gmshInitialize
+%include argcargv.i
+%apply (int ARGC, char **ARGV) { (int argc, char **argv) }
+
 %{
   #include "gmsh.h"
 %}

demos/api/t1.py

@@ -50,7 +50,6 @@ gmshModelGeoAddLine(2, 3, 2);
 gmshModelGeoAddLine(3, 3, 4);
 gmshModelGeoAddLine(4, 4, 1);
 
-
 # The philosophy to construct line loops and surfaces is similar: the second
 # arguments are now vectors of integers.
 gmshModelGeoAddLineLoop(1, [4, 1, -2, 3]);

demos/api/t2.py

@@ -4,13 +4,17 @@
 # API functions used, compared to the ones introduced in t1.py.
 
 from gmsh import *
+import sys
+
+# If sys.argv is passed, Gmsh will parse the commandline in the same way as the
+# standalone Gmsh code.
+gmshInitialize(sys.argv);
 
-gmshInitialize();
 gmshOptionSetNumber("General.Terminal", 1);
 
 gmshModelCreate("t2");
 
-# Copied from t1.cpp...
+# Copied from t1.py...
 lc = 1e-2;
 gmshModelGeoAddPoint(1, 0, 0, 0, lc);
 gmshModelGeoAddPoint(2, .1, 0,  0, lc);