Fix %apply typemap

swig-fortran · Aug 22, 2023 · 95905b0 · 95905b0
1 parent f94cae6
commit 95905b0
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Showing 5 changed files with 16 additions and 3 deletions.
diff --git a/Doc/Manual/Fortran.html b/Doc/Manual/Fortran.html
@@ -1471,7 +1471,7 @@ <H3><a name="Fortran_the_stdstring_class">25.5.1 The std::string class</a></H3>
 
 
 <div class="code"><pre><code>%include &lt;std_string.i&gt;
-%apply std::string { std::string&amp; }</code></pre></div>
+%apply std::string const&amp; { std::string&amp; }</code></pre></div>
 
 <H3><a name="Fortran_stdvector">25.5.2 std::vector</a></H3>
 

diff --git a/Doc/Manual/src/Fortran.md b/Doc/Manual/src/Fortran.md
@@ -1160,7 +1160,7 @@ like pass-by-value strings (where changes to the value in one language will
 *not* make changes in the other), use `%apply`:
 ```swig
 %include <std_string.i>
-%apply std::string { std::string& }
+%apply std::string const& { std::string& }
 ```
 
 ## std::vector

diff --git a/Examples/fortran/std_string/example.h b/Examples/fortran/std_string/example.h
@@ -8,3 +8,7 @@ std::string halved_str(std::string s);
 
 std::string reversed_str(const std::string &input);
 
+inline std::string reversed_str_mutable(std::string &input) {
+  return reversed_str(const_cast<const std::string &>(input));
+}
+
diff --git a/Examples/fortran/std_string/example.i b/Examples/fortran/std_string/example.i
@@ -8,6 +8,9 @@
 // Support native string conversions
 %include <std_string.i>
 
+// Demonstrate using a typemap to treat a mutable string as reference
+%apply const std::string & { std::string& };
+
 %include "example.h"
 
 

diff --git a/Examples/fortran/std_string/runme.f90 b/Examples/fortran/std_string/runme.f90
@@ -2,7 +2,7 @@
 
 program main
   use, intrinsic :: ISO_C_BINDING
-  use example, only : print_str, halved_str, reversed_str
+  use example
   use ISO_FORTRAN_ENV
   implicit none
   integer, parameter :: STDOUT = OUTPUT_UNIT
@@ -39,6 +39,12 @@ program main
   tempstr = reversed_str(tempstr)
 
   write(STDOUT, *) "'"//sampletext//"' -> '"//tempstr//"'"
+
+  write(STDOUT, *) "Reversed mutable"
+  tempstr = reversed_str_mutable(tempstr)
+
+  write(STDOUT, *) "double reversed: -> '"//tempstr//"'"
+
 end program