From 2824b0cbb66e715490e1ef13250bd675d87b32d9 Mon Sep 17 00:00:00 2001 From: William S Fulton Date: Wed, 2 Jun 2010 20:53:17 +0000 Subject: rel-2.0.0 git-svn-id: https://swig.svn.sourceforge.net/svnroot/swig/tags/rel-2.0.0@12089 626c5289-ae23-0410-ae9c-e8d60b6d4f22 --- trunk/Examples/python/funcptr/Makefile | 20 +++++++ trunk/Examples/python/funcptr/example.c | 19 +++++++ trunk/Examples/python/funcptr/example.h | 9 ++++ trunk/Examples/python/funcptr/example.i | 16 ++++++ trunk/Examples/python/funcptr/index.html | 90 ++++++++++++++++++++++++++++++++ trunk/Examples/python/funcptr/runme.py | 20 +++++++ 6 files changed, 174 insertions(+) create mode 100644 trunk/Examples/python/funcptr/Makefile create mode 100644 trunk/Examples/python/funcptr/example.c create mode 100644 trunk/Examples/python/funcptr/example.h create mode 100644 trunk/Examples/python/funcptr/example.i create mode 100644 trunk/Examples/python/funcptr/index.html create mode 100644 trunk/Examples/python/funcptr/runme.py (limited to 'trunk/Examples/python/funcptr') diff --git a/trunk/Examples/python/funcptr/Makefile b/trunk/Examples/python/funcptr/Makefile new file mode 100644 index 000000000..0f4a1e077 --- /dev/null +++ b/trunk/Examples/python/funcptr/Makefile @@ -0,0 +1,20 @@ +TOP = ../.. +SWIG = $(TOP)/../preinst-swig +SRCS = example.c +TARGET = example +INTERFACE = example.i + +all:: + $(MAKE) -f $(TOP)/Makefile SRCS='$(SRCS)' SWIG='$(SWIG)' \ + TARGET='$(TARGET)' INTERFACE='$(INTERFACE)' python + +static:: + $(MAKE) -f $(TOP)/Makefile SRCS='$(SRCS)' SWIG='$(SWIG)' \ + TARGET='mypython' INTERFACE='$(INTERFACE)' python_static + +clean:: + $(MAKE) -f $(TOP)/Makefile python_clean + rm -f $(TARGET).py + +check: all + $(MAKE) -f $(TOP)/Makefile python_run diff --git a/trunk/Examples/python/funcptr/example.c b/trunk/Examples/python/funcptr/example.c new file mode 100644 index 000000000..5c4a3dabf --- /dev/null +++ b/trunk/Examples/python/funcptr/example.c @@ -0,0 +1,19 @@ +/* File : example.c */ + +int do_op(int a, int b, int (*op)(int,int)) { + return (*op)(a,b); +} + +int add(int a, int b) { + return a+b; +} + +int sub(int a, int b) { + return a-b; +} + +int mul(int a, int b) { + return a*b; +} + +int (*funcvar)(int,int) = add; diff --git a/trunk/Examples/python/funcptr/example.h b/trunk/Examples/python/funcptr/example.h new file mode 100644 index 000000000..9936e24fc --- /dev/null +++ b/trunk/Examples/python/funcptr/example.h @@ -0,0 +1,9 @@ +/* file: example.h */ + +extern int do_op(int,int, int (*op)(int,int)); +extern int add(int,int); +extern int sub(int,int); +extern int mul(int,int); + +extern int (*funcvar)(int,int); + diff --git a/trunk/Examples/python/funcptr/example.i b/trunk/Examples/python/funcptr/example.i new file mode 100644 index 000000000..8b3bef678 --- /dev/null +++ b/trunk/Examples/python/funcptr/example.i @@ -0,0 +1,16 @@ +/* File : example.i */ +%module example +%{ +#include "example.h" +%} + +/* Wrap a function taking a pointer to a function */ +extern int do_op(int a, int b, int (*op)(int, int)); + +/* Now install a bunch of "ops" as constants */ +%constant int (*ADD)(int,int) = add; +%constant int (*SUB)(int,int) = sub; +%constant int (*MUL)(int,int) = mul; + +extern int (*funcvar)(int,int); + diff --git a/trunk/Examples/python/funcptr/index.html b/trunk/Examples/python/funcptr/index.html new file mode 100644 index 000000000..e41e0db45 --- /dev/null +++ b/trunk/Examples/python/funcptr/index.html @@ -0,0 +1,90 @@ + + +SWIG:Examples:python:funcptr + + + + + +SWIG/Examples/python/funcptr/ +
+ +

Pointers to Functions

+ +

+Okay, just what in the heck does SWIG do with a declaration like this? + +

+
+int do_op(int a, int b, int (*op)(int, int));
+
+
+ +Well, it creates a wrapper as usual. Of course, that does raise some +questions about the third argument (the pointer to a function). + +

+In this case, SWIG will wrap the function pointer as it does for all other +pointers. However, in order to actually call this function from a script, +you will need to pass some kind of C function pointer object. In C, +this is easy, you just supply a function name as an argument like this: + +

+
+/* Some callback function */
+int add(int a, int b) {
+   return a+b;
+} 
+...
+int r = do_op(x,y,add);
+
+
+ +To make this work with SWIG, you will need to do a little extra work. Specifically, +you need to create some function pointer objects using the %constant directive like this: + +
+
+%constant(int (*)(int,int)) ADD = add;
+
+
+ +Now, in a script, you would do this: + +
+
+r = do_op(x,y, ADD)
+
+
+ +

An Example

+ +Here are some files that illustrate this with a simple example: + + + +

Notes

+ + + +
+ + + + + + diff --git a/trunk/Examples/python/funcptr/runme.py b/trunk/Examples/python/funcptr/runme.py new file mode 100644 index 000000000..bce065057 --- /dev/null +++ b/trunk/Examples/python/funcptr/runme.py @@ -0,0 +1,20 @@ +# file: runme.py + +import example + +a = 37 +b = 42 + +# Now call our C function with a bunch of callbacks + +print "Trying some C callback functions" +print " a =", a +print " b =", b +print " ADD(a,b) =", example.do_op(a,b,example.ADD) +print " SUB(a,b) =", example.do_op(a,b,example.SUB) +print " MUL(a,b) =", example.do_op(a,b,example.MUL) + +print "Here is what the C callback function objects look like in Python" +print " ADD =", example.ADD +print " SUB =", example.SUB +print " MUL =", example.MUL -- cgit v1.2.1