How do I access functions from libsndfile-1.dll in MSVC?

Question

Hi,
  I'm having trouble getting libsndfile-1.dll to work in my MSVC project. I can load the library and retrieve the version string from the dll by calling sf_command() from my code. However, I can't seem to get sf__open() to return a SNDFILE pointer.

I've also noticed that I can't get fopen() to return a FILE pointer either (maybe this is related, I think sf_open() uses fopen()!?).

I'm pretty new to MSVC, C/C++ and windows in general so I'm probably missing something really obvious.

My main.cpp looks like this:

#include <windows.h>
#include <stdio.h>

#include "sndfile.hh"

// create some function pointers to point to the dll function addresses
// I'm winging this a bit. hopefully it's right!? seems to work!
typedef int (*SF_COMMAND)(SNDFILE*, int, void*, int); 
typedef SNDFILE* (*SF_OPEN)(const char*, int, SF_INFO*); 

int main()
{
    // dll handle
    HINSTANCE hDLL = NULL;

    // create some vars to store the dll funcs in
    SF_COMMAND     sf_command;
    SF_OPEN        sf_open;

    // load the dll
    hDLL = LoadLibrary(L"libsndfile-1.dll");

    // check the dll loaded
    if( NULL == hDLL )
    {
        printf("Error, Could not load library \n");
        return 1;
    }

    // get the dll funcs
    sf_command = (SF_COMMAND)GetProcAddress(hDLL, "sf_command");
    sf_open = (SF_OPEN)GetProcAddress(hDLL, "sf_open");

    // check we got the funcs
    if(!(sf_command && sf_open)){
        printf("Error exporting dll functions \n");
        return 2;
    }

    // all good so far!
    // try the first function
    char* version_string[sizeof(char*)*4];
    int res = sf_command(NULL, SFC_GET_LIB_VERSION, &version_string, sizeof(version_string));

    if(res){
        // all good!
        printf("Version: %s \n", version_string);
    }

    // now try and create a SNDFILE pointer
    SF_INFO info;
    SNDFILE* sfp = sf_open("c:\\Godspeed.aif", SFM_READ, &info);

    if(sfp){
        printf("Hurray! successfully opened the SNDFILE!! \n");
    }else{
        printf("Doh! couldn't open the SNDFILE!! \n");
        // Grr!!
        return 3;
    }

    return 0;
}

The project builds and exits with code 3 (couldn't open the file! (I'm pretty sure the file is there!!)).

When I run the exe the output is:
Version: libsndfile-1.0.17
Doh! couldn't open the SNDFILE

Does anyone have any suggestions as to where I'm going wrong?

Many thanks,
Josh.

Answer 1

Hmm, I really should learn not to post to forums late at night! I had another attempt this morning and had the file open within minutes. I was getting my paths all wrong (not used to these weird windows paths)! I tried using a relative path and bingo! Hope that helps someone!