#include <sys/stat.h>
long file_length(char *f)
{
struct stat st;
stat(f, &st);
return st.st_size;
}
If you have the file stream (FILE * f):
fseek(f, 0, SEEK_END); // seek to end of file
size = ftell(f); // get current file pointer
fseek(f, 0, SEEK_SET); // seek back to beginning of file
// proceed with allocating memory and reading the file
Or,
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
fd = fileno(f);
struct stat buf;
fstat(fd, &buf);
int size = buf.st_size;
Or, use stat, if you know the filename:
#include <sys/stat.h>
struct stat st;
stat(filename, &st);
size = st.st_size;