mpg123_open(）和康斯特

我是 c++ 编程的新手，我基本上试图使用 mpg3 制作一个简单的 mp123 播放器，代码在 main（） 中效果很好，但是当我尝试在 sub 中调用它并提交路径+文件播放时，我只是无法让它工作。

GCC抱怨常量字符...和字符转换.."1.c：71：18：错误：从'char'到'const char*'的转换无效[-fallowive]"

#include <ao/ao.h>
#include <mpg123.h>
#define BITS 8
#include <iostream>
using namespace std;
void playaudio(const char * trakl)
{
//works when called here including path
//const char *traklink="/home/pi/downloads/00000050.mp3";
const char * traklink=trakl;

   mpg123_handle *mh;
    unsigned char *buffer;
    size_t buffer_size;
    size_t done;
    int err;
    int driver;
    ao_device *dev;
    ao_sample_format format;
    int channels, encoding;
    long rate;
   /* if(argc < 2)
        exit(0);
*/
    /* initializations */
    ao_initialize();
    driver = ao_default_driver_id();
    mpg123_init();
    mh = mpg123_new(NULL, &err);
    buffer_size = mpg123_outblock(mh);
    buffer = (unsigned char*) malloc(buffer_size * sizeof(unsigned char));
    /* open the file and get the decoding format */
    //mpg123_open(mh,traklink);
    mpg123_open(mh,traklink);
     mpg123_getformat(mh, &rate, &channels, &encoding);
    /* set the output format and open the output device */
   format.bits = mpg123_encsize(encoding) * BITS;
    format.rate = rate;
    format.channels = channels;
    format.byte_format = AO_FMT_NATIVE;
    format.matrix = 0;
    dev = ao_open_live(driver, &format, NULL);
    /* decode and play */
    while (mpg123_read(mh, buffer, buffer_size, &done) == MPG123_OK)
        //ao_play(dev, buffer, done);
        ao_play(dev, (char*)buffer, done);
    /* clean up */
    free(buffer);
    ao_close(dev);
    mpg123_close(mh);
    mpg123_delete(mh);
    mpg123_exit();
    ao_shutdown();
//  return 0;
}
int main()
{
const char * trakl="/home/pi/downloads/00000050.mp3";
playaudio(* trakl);
return 0;
}