Python-list Digest, Vol 66, Issue 527

steve William steve.william at gmail.com
Fri Mar 27 18:42:24 CET 2009


>
> steve William wrote:
>
>> Hi All,
>>
>> I'm using SWIG for the first time and I am facing some problems with user
>> defined header files. I'm trying to use my own header file in a C program
>> which would be interfaced with python.
>>
>> The header file is test.h:
>> /#include <stdio.h>
>>
>> int fact(int n) {
>>     if (n <= 1) return 1;
>>     else return n*fact(n-1);
>> }/
>>   The C program is test1.c:
>> /#include <stdio.h>
>> #include "test.h"
>>
>> int calc_fact(int a)
>> {
>>    return (fact(a));
>> }/
>>
>> The interface file is test1.i:
>> /%module test1
>>
>> %{
>> #include "stdio.h"
>> #include "test.h"
>>  %}
>>
>> int calc_fact(int a);/
>>
>> The commands that I used to generate the wrappers are:
>> /swig -python test1.i
>> gcc -c test1.c test1_wrap.c -I/usr/include/python2.5
>> -I/usr/lib/python2.5/config
>> g++ -shared test1_wrap.o -o _test1.so/
>>
>> When I try to import test1, I get an error saying:
>> />>> import test1
>> Traceback (most recent call last):
>>  File "<stdin>", line 1, in <module>
>>  File "test1.py", line 22, in <module>
>>    import _test1
>> ImportError: ./_test1.so: undefined symbol: calc_fact/
>>
>> I'm not sure why this is happening because when I try without user defined
>> header file, it works. Also the error says that it does not recognize
>> /calc_fact/ which is a function that I want to access from python and is
>> declared in the interface file.
>>
>> Is there any specific way in which user defined headers need to be
>> declared in the interface file? Should the user defined header be placed in
>> the /usr/include  directory?
>>
>> Any help on this is highly appreciated.
>>
>>  Should you be putting a function body in a header file?
>

Since the header is pretty simple it does not do any harm putting the
function body in the header. It does compile and run correctly in gcc.
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