C++中调用C方法(文件)的典型做法

extern "C" {
	extern int file_trans_aac_2_pcm(int ifd, int ofd);
}

#include "AudioHelper.h"
...
file_trans_aac_2_pcm(...);

#ifndef _AUDIOHELPER_H_
#define _AUDIOHELPER_H_
int file_trans_aac_2_pcm(int ifd, int ofd);
#endif // _AUDIOHELPER_H_

#include "AudioHelper.h"
int file_trans_aac_2_pcm(int ifd, int ofd)
{
	...
}