source: contrib/API/tools/pcmconv.c

#define INCL_DOS
#define INCL_DOSERRORS
#include <os2.h>
#include <stdlib.h>
#include <stdio.h>
#include <io.h>
#include <fcntl.h>
#include <conio.h>
#include <math.h>

int main (int argc, char *argv[])
{
    int ArgNum;
    int ver, err, ret;
    int channels,i, bytesread, count;
    int card_id = 0;
    char *Buffer;
    char *Buf;
    int readed, written, state, fsize;
    FILE *input_handle;
    FILE *output_handle;


    printf("PCM convert tool. Version 0.01\n");
    printf("Copyright 2004 by Vlad Stelmahosky aka Vladest\n");

    if (argc > 1)
        input_handle = fopen(argv[1], "rb");
    else
        input_handle = fopen("debug.wav", "rb");
    if (!input_handle) printf("Error opening input file\n");

    if (argc > 2)
        output_handle = fopen(argv[1], "wb");
    else
        output_handle = fopen("debug6ch.wav", "wb");
    if (!output_handle) printf("Error opening output file\n");
    fseek(input_handle, 0L, SEEK_END);
    fsize = ftell(input_handle);
    Buffer = malloc(fsize);
    fseek(input_handle, 0L, SEEK_SET);
    //        memset(Buffer,0, count);
    bytesread = fread (Buffer, 1, fsize, input_handle);
    fclose(input_handle);

    for(i=0; i < bytesread;i+=4)
    {
        fwrite (Buffer+i, 1, 4, output_handle);
        fwrite (Buffer+i, 1, 4, output_handle);
        fwrite (Buffer+i, 1, 4, output_handle);
    }

    fclose(output_handle);
    return 0;
}