File size in bytes

I was wondering if there is a more efficent way to calculate actual size in bytes of any file,
here is how I am doing.
win32 API which will do it for me. accuracy is important as I will be reading the entire file in to a shared buffer.

Code:

---

fstream reader("myfile",std:ios:binary| std::ios::in);
unsigned int counter =0;
unsigned char myReader;
while(!reader.eof)
{
  reader.read((char *)&myReader,sizeof(unsigned char));
  counter++
}
reader.close();
unsigned int filesize = counter;

---

I am hoping how many times the loops run will tell me the actual size in bytes. Once I know what the size is then I can allocate memory and read the entire file all at once in to the shared buffer.

Did you try _filelength, _filelengthi64?

Code:

---

#include <stat/sys>
struct stat stbuf;
stat("/tmp/file.txt", &stbuf);
size_t size = stbuf.st_size;

---

Maybe this would help.

http://www.cplusplus.com/reference/i...istream/tellg/

Since you mentioned the Win32 API you might consider GetFileSize or GetFileSizeEx.

thank you all