linux C++ 获取文件绝对路径

#include <stdlib.h>
#include <stdio.h>
#include <limits.h>

int main(){
const char *file_name = "filename";
char abs_path_buff[PATH_MAX];

//获取文件路径, 填充到abs_path_buff
//realpath函数返回: null表示获取失败; 否则返回指向abs_path_buff的指针
if(realpath(file_name, abs_path_buff)){
printf("%s %s\n", file_name, abs_path_buff);
}
else{
printf("the file '%s' is not exist\n", file_name);
}

return 0;
}