Re: Re: using stdout/stderr with python

Luigi:

Could you add the attached files to CVS?

 file.i  -> Lib/python
 file_test.i, file_test_runme.py -> Examples/test-suite/python

I still don't know how to make the new CVS rep. work for me.

Anyway, the file.i should be used as usual


%module mymodule
...
%include file.i
...

int myfunc(FILE *file);
...

and it will provide the proper 'in' typemaps. Then you can call:

import sys
import mymodule
....
mymodule.myfunc(sys.stdout)



See the file_test_runme.py for more examples.

Marcelo


Luigi Ballabio wrote:

> On 2004.05.25 17:48, Kevin Smith wrote:
>
> > Martin F Krafft wrote:
> >
> > > > Some of my functions take a FILE*. I understand how one can
> > > > provide wrappers or a typemap to deal with that, but what if
> > > > I want to pass stdout and stderr into these functions as the FILE*
> > > > arguments? I could not find a way to do this.
> >
> > One way would be to create C functions like GetStdin and GetStdout,  
> > and wrap them. This way, from Python, you could get access to FILE*  
> > versions of those streams. Then, you can pass those values back into  
> > your other functions.
>
>
> This wouldn't help when next he wants to pass a Python file handle  
> created with open(). From a quick look at the Python/C API (see
> http://www.python.org/doc/2.3.3/api/fileObjects.html) the following  
> might work:
>
> %typemap(in) FILE* {
>    if (PyFile_Check($input)) {
>        $1 = PyFile_AsFile($input);
>    } else {
>        SWIG_exception(SWIG_TypeError, "file expected"),
>    }
> }
>
> but I haven't tested it, so I don't guarantee that it won't cause  
> scripts to crash horribly.
>
> Hope this helps,
>     Luigi
> _______________________________________________
> Swig maillist  -  Swig@xxxxxxxxxxxxxxx
> http://mailman.cs.uchicago.edu/mailman/listinfo/swig


/*
  Typemaps for FILE*

  From the ideas of Luigi 
  luigi.ballabio@xxxxxxxxxxxxx
*/

%types(FILE *);

/* defining basic methods */
%fragment("SWIG_AsValFilePtr","header") {
SWIGSTATICINLINE(int)
SWIG_AsValFilePtr(PyObject *obj, FILE **val) {
  static swig_type_info* desc = 0;
  FILE *ptr = 0;
  if (!desc) desc = SWIG_TypeQuery("FILE *");
  if ((SWIG_ConvertPtr(obj,(void **)(&ptr), desc, 0)) != -1) {
    if (val) *val = ptr;
    return 1;
  } 
  if (PyFile_Check(obj)) {
    if (val) *val =  PyFile_AsFile(obj);
    return 1;
  }
  if (val) PyErr_SetString(PyExc_TypeError, "a FILE* is expected");
  return 0;
}
}

%fragment("SWIG_AsFilePtr","header",fragment="SWIG_AsValFilePtr") {
SWIGSTATICINLINE(FILE*)
SWIG_AsFilePtr(PyObject *obj) {
  FILE *val = 0;
  SWIG_AsValFilePtr(obj, &val);
  return val;
}
}

%fragment("SWIG_CheckFilePtr","header",fragment="SWIG_AsValFilePtr") {
SWIGSTATICINLINE(int)
SWIG_CheckFilePtr(PyObject *obj) {
  return SWIG_AsValFilePtr(obj, (FILE **)(0));
}
}

/* defining the typemaps */
%typemap_ascheck(SWIG_CCode(POINTER), SWIG_AsFilePtr, SWIG_CheckFilePtr,
                 "SWIG_AsFilePtr", "SWIG_CheckFilePtr", FILE*);
%module file_test

%include file.i


%inline 
%{
  int nfile(FILE *file) {
    printf("hello %p\n", (void*)file);
    if (file) {
      // fprintf(file,"hello\n");
    }
    return 0;
  }

  int nfile(const char *filename) {
    FILE *file = fopen(filename,"w");
    nfile(file);
    fclose(file);
    return 0;
  }

  FILE* GetStdOut() {
    return stdout;
  }
  
%}

import sys
import file_test

file_test.nfile(sys.stdout)

cstdout = file_test.GetStdOut()

file_test.nfile(cstdout)
file_test.nfile("test.dat")