<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN""http://www.w3.org/TR/html4/loose.dtd"> <HTML ><HEAD ><TITLE >FAQs</TITLE ><META NAME="GENERATOR" CONTENT="Modular DocBook HTML Stylesheet Version 1.79"><LINK REL="HOME" TITLE="The findlib User's Guide" HREF="index.html"><LINK REL="UP" TITLE="User's Guide" HREF="p35.html"><LINK REL="PREVIOUS" TITLE="Using the Makefile wizard" HREF="x372.html"><LINK REL="NEXT" TITLE="Why does findlib not automatically include the -custom option if linked with C code?" HREF="x394.html"></HEAD ><BODY CLASS="CHAPTER" BGCOLOR="#FFFFFF" TEXT="#000000" LINK="#0000FF" VLINK="#840084" ALINK="#0000FF" ><DIV CLASS="NAVHEADER" ><TABLE SUMMARY="Header navigation table" WIDTH="100%" BORDER="0" CELLPADDING="0" CELLSPACING="0" ><TR ><TH COLSPAN="3" ALIGN="center" >The findlib User's Guide</TH ></TR ><TR ><TD WIDTH="10%" ALIGN="left" VALIGN="bottom" ><A HREF="x372.html" ACCESSKEY="P" >Prev</A ></TD ><TD WIDTH="80%" ALIGN="center" VALIGN="bottom" ></TD ><TD WIDTH="10%" ALIGN="right" VALIGN="bottom" ><A HREF="x394.html" ACCESSKEY="N" >Next</A ></TD ></TR ></TABLE ><HR ALIGN="LEFT" WIDTH="100%"></DIV ><DIV CLASS="CHAPTER" ><H1 ><A NAME="AEN380" ></A >Chapter 7. FAQs</H1 ><DIV CLASS="TOC" ><DL ><DT ><B >Table of Contents</B ></DT ><DT ><A HREF="c380.html#AEN382" >Does findlib support the autolink feature of O'Caml 3?</A ></DT ><DT ><A HREF="x394.html" >Why does findlib not automatically include the -custom option if linked with C code?</A ></DT ><DT ><A HREF="x400.html" >Does findlib support linking of applications as well as packages?</A ></DT ><DT ><A HREF="x412.html" >Does Findlib support camlp4?</A ></DT ><DT ><A HREF="x464.html" >Why do some people install the .cmx files?</A ></DT ><DT ><A HREF="x468.html" >How do I express conflicts?</A ></DT ></DL ></DIV ><DIV CLASS="SECT1" ><H1 CLASS="SECT1" ><A NAME="AEN382" >Does findlib support the autolink feature of O'Caml 3?</A ></H1 ><P ><SPAN CLASS="emphasis" ><I CLASS="EMPHASIS" >Short answer:</I ></SPAN > Findlib is compatible with autolink</P ><P >The new archive format introduced with O'Caml 3 can store the linker options that are necessary to link an archive. For example: <PRE CLASS="PROGRAMLISTING" >ocamlc -a -o myarchive.cma mymodule.cmo -cclib -lmylibrary</PRE > This command does not only create the new archive <TT CLASS="LITERAL" >myarchive.cma</TT >, but it also writes into a special section of that file that the linker option <TT CLASS="LITERAL" >-cclib -lmylibrary</TT > is necessary to link this archive.</P ><P >This means for findlib that most of the "linkopts" attributes in META files have become superflous: The compiler itself already knows the linker options, we do not need to tell the compiler the options. We could simply leave all "linkopts" attributes out.</P ><P >Of course, the "linkopts" feature of findlib still works. This is necessary because findlib should keep the compatibility with older software, and because "linkopts" is more powerful (you can have conditional linker options).</P ><P >If you have software that must run in both O'Caml 2 and O'Caml 3 environments, you can make your "linkopts" attribute dependent on the "autolink" predicate. For example: <PRE CLASS="PROGRAMLISTING" >linkopts = "-cclib -lmylibrary" linkopts(autolink) = ""</PRE > The findlib installation for O'Caml 3 will take the second line which is reasonable because ocamlc already knows how to link; the installation for O'Caml 2 never sets the "autolink" predicate and therefore uses the first line.</P ></DIV ></DIV ><DIV CLASS="NAVFOOTER" ><HR ALIGN="LEFT" WIDTH="100%"><TABLE SUMMARY="Footer navigation table" WIDTH="100%" BORDER="0" CELLPADDING="0" CELLSPACING="0" ><TR ><TD WIDTH="33%" ALIGN="left" VALIGN="top" ><A HREF="x372.html" ACCESSKEY="P" >Prev</A ></TD ><TD WIDTH="34%" ALIGN="center" VALIGN="top" ><A HREF="index.html" ACCESSKEY="H" >Home</A ></TD ><TD WIDTH="33%" ALIGN="right" VALIGN="top" ><A HREF="x394.html" ACCESSKEY="N" >Next</A ></TD ></TR ><TR ><TD WIDTH="33%" ALIGN="left" VALIGN="top" >Using the Makefile wizard</TD ><TD WIDTH="34%" ALIGN="center" VALIGN="top" ><A HREF="p35.html" ACCESSKEY="U" >Up</A ></TD ><TD WIDTH="33%" ALIGN="right" VALIGN="top" >Why does findlib not automatically include the -custom option if linked with C code?</TD ></TR ></TABLE ></DIV ></BODY ></HTML >