hi, i am trying to write a small FTP server.
now after all the normal authentication here is what i want to do.
check whether the selected file is there or not?
if it is there start tranfering it in binary mode.
now there is one problem i have doing this.
the sysread function has the following arguments.
sysread(FILEHANDLE, $scalar, $LENGTH)
Attempts to read LENGTH bytes of data into variable SCALAR
from the specified FILEHANDLE, using the system call read().
now the thing is that how do i know what length a file is.
cause every file will have a different length so i have to know the length of the file before i transfer it.
so how do i know what length a file is. REMEMBER THE FILE HAS TO BE TRANSFERED IN BINARY that is the mode of the handle will be changed to binary using binmode function.
secondly can any one tell me that if i syswrite() a file to socket how can i read it back at the client end using sysread or syswrite functions.
plz explain with little code.

In reply to explanation for sysread and syswrite by bahadur

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.