我是 C++ 编程的新手，我基本上是在尝试使用 mpg123 制作一个简单的 mp3 播放器，代码在 main() 中运行良好，但是当我尝试在 sub 中调用它并提交路径+文件来播放时，我就是不能让它工作。
gcc 抱怨 const char... 和 char 转换...“1.c:71:18: 错误：从 'char' 到 'const char*' [-fpermissive] 的无效转换”
#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;
}