<title>Forcing options to a particular phase</title>
<indexterm><primary>forcing GHC-phase options</primary></indexterm>
- <para>Options can be forced through to a particlar compilation
+ <para>Options can be forced through to a particular compilation
phase, using the following flags:</para>
<variablelist>
<listitem>
<para>This symbol is defined when pre-processing Haskell
(input) and pre-processing C (GHC output). Since GHC from
- verion 4.00 now supports concurrent haskell by default,
+ version 4.00 now supports concurrent haskell by default,
this symbol is always defined.</para>
</listitem>
</varlistentry>
<listitem>
<para>When generating code, assume that entities imported from a
different package will reside in a different shared library or
- binary. This currently works on Mac OS X; it works on PowerPC Linux when
- using the native code generator. As with <option>-fPIC</option>,
- x86 Linux support is not quite ready yet. Windows is not supported,
- and it is a no-op on PowerPC64 Linux.</para>
+ binary.</para>
<para>Note that this option also causes GHC to use shared libraries
when linking.</para>
</listitem>
<indexterm><primary><option>-dynamic</option></primary></indexterm>
</term>
<listitem>
- <para>Tell the linker to use shared Haskell libraries, if
- available (this option is only supported on Mac OS X at the
- moment, and also note that your distribution of GHC may
- not have been supplied with shared libraries).</para>
+ <para>This flag switches to shared Haskell libraries for
+ linking. See <xref linkend="building-packages" /> on how to
+ create them.</para>
+
<para>Note that this option also has an effect on
code generation (see above).</para>
</listitem>
<varlistentry>
<term>
+ <option>-shared</option>
+ <indexterm><primary><option>-shared</option></primary></indexterm>
+ </term>
+ <listitem>
+ <para>Instead of creating an executable, GHC produces a
+ shared object with this linker flag. Depending on the
+ operating system target, this might be an ELF DSO, a Windows
+ DLL, or a Mac OS dylib. GHC hides the operating system
+ details beneath this uniform flag.</para>
+
+ <para>The flags <option>-dynamic</option>/<option>-static</option> control whether the
+ resulting shared object links statically or dynamically to
+ Haskell package libraries given as <option>-package</option> option. Non-Haskell
+ libraries are linked as gcc would regularly link it on your
+ system, e.g. on most ELF system the linker uses the dynamic
+ libraries when found.</para>
+
+ <para>Object files linked into shared objects must be
+ compiled with <option>-fPIC</option>, see <xref linkend="options-codegen" /></para>
+
+ <para>When creating shared objects for Haskell packages, the
+ shared object must be named properly, so that GHC recognizes
+ the shared object when linked against this package. See
+ shared object name mangling.</para>
+ </listitem>
+ </varlistentry>
+
+
+ <varlistentry>
+ <term>
<option>-main-is <replaceable>thing</replaceable></option>
<indexterm><primary><option>-main-is</option></primary></indexterm>
<indexterm><primary>specifying your own main function</primary></indexterm>