-
+ +-Original Datatype caststr() +Original Datatype rcaststr() ------------------ --------- char *a const char *a (const char *) name @@ -480,6 +480,27 @@ double &a (double &) *name
+
+++Original Datatype lcaststr() +------------------ --------- +char *a +const char *a (char *) name +double a[20] (double *) name +double a[20][30] (double *) name +double &a (double *) &name ++
+When generating wrappers, SWIG tries to provide a mostly +seamless with the original code. However, there are a number of +problematic features of C/C++ that are handled in the following manner: + +
++ +gets turned into a wrapper like this: + ++double dot_product(Vector a, Vector b); ++
+
+double wrap_dot_product(Vector *a, Vector *b) {
+ return dot_product(*a,*b);
+}
+
+
+
+Functions that return by value require a memory allocation to store the result. For example:
+
+++ +become + ++Vector cross_product(Vector *a, Vector *b); ++
+
+Vector *wrap_cross_product(Vector *a, Vector *b) {
+ Vector *result = (Vector *) malloc(sizeof(Vector));
+ *result = cross_product(a,b);
+ return result;
+}
+
+
+
+Note: If C++ is being wrapped, the default copy constructor is used
+instead of malloc() to create a copy of the return result.
+
++
+
+
+
+
+
+
+
+
++ +Here's how you might write a really simple wrapper function + ++double dot_product(Vector a, Vector b); ++
+
+ParmList *l = ... parameter list of the function ...
+DataType *t = ... return type of the function ...
+char *name = ... name of the function ...
+Wrapper *w = NewWrapper();
+Printf(w->def,"void wrap_%s() {\n", name);
+
+/* Declare all of the local variables */
+Swig_cargs(w, l);
+
+/* Convert all of the arguments */
+...
+
+/* Make the function call and declare the result variable */
+Swig_cresult(w,t,"result",Swig_cfunction(name,l));
+
+/* Convert the result into whatever */
+...
+
+Printf(w->code,"}\n");
+Wrapper_print(w,out);
+
+
+
+The output of this would appear as follows:
+
+
+
+void wrap_dot_product() {
+ Vector *arg0;
+ Vector *arg1;
+ double result;
+
+ ...
+ result = dot_product(*arg0, *arg1);
+ ...
+}
+
+
+
+Notice that the Swig_cargs(), Swig_cresult(), and Swig_cfunction() functions
+have taken care of the type conversions for the Vector type automatically.
+
++Notes: +
+