CODEWITHSUNDEEP
pythoncpointersparametersswig
limenuke
limenuke

Reputation: 53

How to implement pointer of typedef'd variable into SWIG? argument 2 of type 'BYTE const *' error

I am setting up a Python-C SWIG interface right now. I've already gotten it to produce the shared object file through the following commands:

swig -python myFile.i

gcc -c myFile.c myFile2.c myFile3.c myFile_wrap.c -IC:\myincludedirectory\include

gcc -shared myFile.o myFile2.o myFile3.o myFile_wrap.o -Ic:\myincludedirectory\libs -lpython27 -o _myfile3.o

In myFile.i, I have:

/*  myFile3 */
%module myFile3

%{
    #include "myFile.h"
    #include "defs.h"
    #include "myFile2.h"
    #include "myFile3.h"

%}
    %include "defs.h"
    %include "myFile.h" 
    %include "myFile2.h"
    %include "myFile3.h"

defs.h contains the following lines (among others):

typedef unsigned int BOOL;
typedef unsigned short WORD;    //Word is 2 bytes but int* is 4 bytes ??
typedef unsigned int DWORD;
typedef unsigned long long QWORD;
typedef unsigned char BYTE;

When I attempt to call my program, I do the following in command prompt:

python

import myFile3

myFile3.myFuncInit()

myFile3.myFuncWrite ("ABCD", "ABCDEFGHI", 8); // <= I get an error when I enter this line.

where myFuncWrite's parameters are (char *param1, const BYTE *param2, WORD param3)

I believe the issue lies in the fact that it's a const BYTE pointer. I am not sure if I need to do some simple helper function or a typemap to get it to pass properly. As it is, I keep getting stuck here and I've no idea what I should do to get swig to understand I'm simply passing a pointer of BYTE's typedef.

Upvotes: 2

Views: 1323

Answers (1)

Asher L.
Asher L.

Reputation: 1297

After the %include "defs.h line, try adding this line:

%apply char* {BYTE*};

This will apply all of the char* typemaps (including type-checking) to BYTE*. For more on this, read the following section of the SWIG manual:

http://www.swig.org/Doc2.0/Typemaps.html#Typemaps_nn6

Upvotes: 3

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