check the size of the file in linux code example

Example 1: linux file size

cd dir ; du -hsx * | sort -rh | head -20 
# example output
# 300MB    some_backup_file.log
# 1.8GB    some_huge_file.war

Example 2: how to check the size of a file in linux c

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;