How to find length of a file? 1

[Flappy]

Is it possible to find the length of a file before I read it? so i can just malloc the memory and read the file into it?

 

[itsgsd]

Yes, it is possible, what OS and compiler are you using, and are you opening the file as a stream (fopen) or handle/file descriptor using open?

Look at the stat and fstat functions.

Alternatively, on an open file you can do:

for a stream:

FILE *fi = fopen("filename","r");
fseek(fi,0,SEEK_END);
length = tell(fi);
rewind(fi);

Also, some compilers had a filelength function for file descriptors.

Good luck.

for a file descriptor:

int handle=open("filename"...);
length = lseek(handle,O,SEEK_END);
lseek(handle,0,SEEK_SET);

Good luck.

 

[Flappy]

Thanks that should do the trick - I'm using stream so I'll use your first example there. I'm using Linux but will eventually port it over to Win32.

 

[dsanchez2]

On Linux (or UNIX) try:

#include <sys/stat.h>

main()
{
struct stat buf;

if (stat("filename",&buf) != -1)
printf("Size: %d\n",buf.st_size);
else
printf("---ERROR---\n");

}

The stat call returns information about the given file into the structure "buf". On of the fields in this structure is the file size.