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Full Discussion: [c] How to calculate size of the file from size of the buffer?
Top Forums Programming [c] How to calculate size of the file from size of the buffer? Post 302656147 by jim mcnamara on Thursday 14th of June 2012 09:55:10 AM
Old 06-14-2012
It is not guaranteed to work. Use stat() to get a file size.
Code:
#include <sys/stat.h>
size_t filesize(int fd)
{
     struct stat st;
     if(fstat(fd, &st) == -1 )
     {
          perror("cannot stat file");
          exit(1);
      }
     return st.st_size;
}

void myfoo(void)
{
    size_t bytes;
    //.......... your code here
     bytes=filesize(fileno(fic_sortie));
    //.......  more code here
}

try something like that.
 

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LEARN ABOUT DEBIAN

explain_stat_or_die

explain_stat_or_die(3)					     Library Functions Manual					    explain_stat_or_die(3)

NAME

       explain_stat_or_die - get file status and report errors

SYNOPSIS

       #include <libexplain/stat.h>
       void explain_stat_or_die(const char *pathname, struct stat *buf);

DESCRIPTION

       The  explain_stat_or_die  function  is used to call the stat(2) system call.  On failure an explanation will be printed to stderr, obtained
       from explain_stat(3), and then the process terminates by calling exit(EXIT_FAILURE).

       This function is intended to be used in a fashion similar to the following example:
	      explain_stat_or_die(pathname, buf);

       pathname
	       The pathname, exactly as to be passed to the stat(2) system call.

       buf     The buf, exactly as to be passed to the stat(2) system call.

       Returns:
	       This function only returns on success.  On failure, prints an explanation and exits.

SEE ALSO

       stat(2) get file status

       explain_stat(3)
	       explain stat(2) errors

       exit(2) terminate the calling process

COPYRIGHT

       libexplain version 0.52
       Copyright (C) 2008 Peter Miller

															    explain_stat_or_die(3)
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