comment on

As said, you get the SIPGPIPE immediately after the first unsuccessful write, so you may want to keep your amount of lines short for each write.

If you have control of the child you could make it send a HUP or USR1 to its parent after closing the file handle.

Update: Oh I see you haven't, a compiled C program... hm. A wrapper, maybe?

perl -le'print map{pack c,($-++?1:13)+ord}split//,ESEL'

Are you posting in the right place? Check out Where do I post X? to know for sure.
Posts may use any of the Perl Monks Approved HTML tags. Currently these include the following:
<code> <a> <b> <big> <blockquote> <br /> <dd> <dl> <dt> <em> <font> <h1> <h2> <h3> <h4> <h5> <h6> <hr /> <i> <li> <nbsp> <ol> <p> <small> <strike> <strong> <sub> <sup> <table> <td> <th> <tr> <tt> <u> <ul>
Snippets of code should be wrapped in <code> tags not <pre> tags. In fact, <pre> tags should generally be avoided. If they must be used, extreme care should be taken to ensure that their contents do not have long lines (<70 chars), in order to prevent horizontal scrolling (and possible janitor intervention).
Want more info? How to link or How to display code and escape characters are good places to start.