SWIG problems with gcc and Cygwin?

Michael Yanowitz m.yanowitz at kearfott.com
Tue Jun 20 21:39:07 CEST 2006


Hello:

   I am just trying out SWIG, but quickly ran into problems.
Using Cygwin gcc, I tried the following:

1) Created example.c (as given on http://www.swig.org/tutorial.html )
/* File : example.c */

 #include <time.h>
 double My_variable = 3.0;

 int fact(int n) {
     if (n <= 1) return 1;
     else return n*fact(n-1);
 }

 int my_mod(int x, int y) {
     return (x%y);
 }

 char *get_time()
 {
     time_t ltime;
     time(&ltime);
     return ctime(&ltime);
 }

2) Create interface file, example.i

/* example.i */
 %module example
 %{
 /* Put header files here or function declarations like below */
 extern double My_variable;
 extern int fact(int n);
 extern int my_mod(int x, int y);
 extern char *get_time();
 %}

 extern double My_variable;
 extern int fact(int n);
 extern int my_mod(int x, int y);
 extern char *get_time();

3)ran in cygwin:  swig -i python example.i

4)Attempted to run on cygwin:  ld -shared example.o example_wrap.o -o
_example.so
But got back many errors:
example.o:example.c:(.text+0x55): undefined reference to `time'
example.o:example.c:(.text+0x60): undefined reference to `ctime'
example_wrap.o:example_wrap.c:(.text+0x9c): undefined reference to `strlen'
example_wrap.o:example_wrap.c:(.text+0x12c): undefined reference to `strlen'
example_wrap.o:example_wrap.c:(.text+0x1dd): undefined reference to `strcmp'
example_wrap.o:example_wrap.c:(.text+0x494): undefined reference to `strcmp'
example_wrap.o:example_wrap.c:(.text+0x748): undefined reference to `strlen'
example_wrap.o:example_wrap.c:(.text+0x779): undefined reference to `strcpy'
example_wrap.o:example_wrap.c:(.text+0x7a5): undefined reference to `strcmp'
example_wrap.o:example_wrap.c:(.text+0x805): undefined reference to `strlen'
example_wrap.o:example_wrap.c:(.text+0x877): undefined reference to
`strncpy'
example_wrap.o:example_wrap.c:(.text+0x8ab): undefined reference to `strcmp'
example_wrap.o:example_wrap.c:(.text+0x8c9): undefined reference to `memset'
example_wrap.o:example_wrap.c:(.text+0x948): undefined reference to `fputs'
example_wrap.o:example_wrap.c:(.text+0x95d): undefined reference to `fputs'
example_wrap.o:example_wrap.c:(.text+0x970): undefined reference to `fputs'
example_wrap.o:example_wrap.c:(.text+0x9db): undefined reference to
`PyString_Fr
omFormat'
example_wrap.o:example_wrap.c:(.text+0xa3a): undefined reference to
`PyString_Fr
omString'
example_wrap.o:example_wrap.c:(.text+0xa68): undefined reference to
`PyLong_From
VoidPtr'
example_wrap.o:example_wrap.c:(.text+0xa83): undefined reference to
`PyTuple_New
  etc...

  Any idea what I am doing wrong or omitted?

Of course when I then try to go into python and
import example, I get:

>>> import example
Traceback (most recent call last):
  File "<stdin>", line 1, in ?
  File "example.py", line 5, in ?
    import _example
ImportError: No module named _example

Thanks in advance:
Michael Yanowitz




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