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</script></head><body><div id="package-header"><ul class="links" id="page-menu"><li><a href="index.html">Contents</a></li><li><a href="doc-index.html">Index</a></li></ul><p class="caption">base-4.5.1.0: Basic libraries</p></div><div id="content"><div id="module-header"><table class="info"><tr><th>Portability</th><td>portable</td></tr><tr><th>Stability</th><td>provisional</td></tr><tr><th>Maintainer</th><td>ffi@haskell.org</td></tr><tr><th>Safe Haskell</th><td>Trustworthy</td></tr></table><p class="caption">Foreign.ForeignPtr.Safe</p></div><div id="table-of-contents"><p class="caption">Contents</p><ul><li><a href="#g:1">Finalised data pointers
</a><ul><li><a href="#g:2">Basic operations
</a></li><li><a href="#g:3">Low-level operations
</a></li><li><a href="#g:4">Allocating managed memory
</a></li></ul></li></ul></div><div id="description"><p class="caption">Description</p><div class="doc"><p>The <code><a href="Foreign-ForeignPtr-Safe.html#t:ForeignPtr">ForeignPtr</a></code> type and operations. This module is part of the
Foreign Function Interface (FFI) and will usually be imported via
the <a href="Foreign.html">Foreign</a> module.
</p><p>Safe API Only.
</p></div></div><div id="synopsis"><p id="control.syn" class="caption expander" onclick="toggleSection('syn')">Synopsis</p><ul id="section.syn" class="hide" onclick="toggleSection('syn')"><li class="src short"><span class="keyword">data</span> <a href="#t:ForeignPtr">ForeignPtr</a> a</li><li class="src short"><span class="keyword">type</span> <a href="#t:FinalizerPtr">FinalizerPtr</a> a = <a href="Foreign-Ptr.html#t:FunPtr">FunPtr</a> (<a href="Foreign-Ptr.html#t:Ptr">Ptr</a> a -> <a href="System-IO.html#t:IO">IO</a> <a href="../ghc-prim-0.2.0.0/GHC-Tuple.html#t:-40--41-">()</a>)</li><li class="src short"><span class="keyword">type</span> <a href="#t:FinalizerEnvPtr">FinalizerEnvPtr</a> env a = <a href="Foreign-Ptr.html#t:FunPtr">FunPtr</a> (<a href="Foreign-Ptr.html#t:Ptr">Ptr</a> env -> <a href="Foreign-Ptr.html#t:Ptr">Ptr</a> a -> <a href="System-IO.html#t:IO">IO</a> <a href="../ghc-prim-0.2.0.0/GHC-Tuple.html#t:-40--41-">()</a>)</li><li class="src short"><a href="#v:newForeignPtr">newForeignPtr</a> :: <a href="Foreign-ForeignPtr-Safe.html#t:FinalizerPtr">FinalizerPtr</a> a -> <a href="Foreign-Ptr.html#t:Ptr">Ptr</a> a -> <a href="System-IO.html#t:IO">IO</a> (<a href="Foreign-ForeignPtr-Safe.html#t:ForeignPtr">ForeignPtr</a> a)</li><li class="src short"><a href="#v:newForeignPtr_">newForeignPtr_</a> :: <a href="Foreign-Ptr.html#t:Ptr">Ptr</a> a -> <a href="System-IO.html#t:IO">IO</a> (<a href="Foreign-ForeignPtr-Safe.html#t:ForeignPtr">ForeignPtr</a> a)</li><li class="src short"><a href="#v:addForeignPtrFinalizer">addForeignPtrFinalizer</a> :: <a href="Foreign-ForeignPtr-Safe.html#t:FinalizerPtr">FinalizerPtr</a> a -> <a href="Foreign-ForeignPtr-Safe.html#t:ForeignPtr">ForeignPtr</a> a -> <a href="System-IO.html#t:IO">IO</a> <a href="../ghc-prim-0.2.0.0/GHC-Tuple.html#t:-40--41-">()</a></li><li class="src short"><a href="#v:newForeignPtrEnv">newForeignPtrEnv</a> :: <a href="Foreign-ForeignPtr-Safe.html#t:FinalizerEnvPtr">FinalizerEnvPtr</a> env a -> <a href="Foreign-Ptr.html#t:Ptr">Ptr</a> env -> <a href="Foreign-Ptr.html#t:Ptr">Ptr</a> a -> <a href="System-IO.html#t:IO">IO</a> (<a href="Foreign-ForeignPtr-Safe.html#t:ForeignPtr">ForeignPtr</a> a)</li><li class="src short"><a href="#v:addForeignPtrFinalizerEnv">addForeignPtrFinalizerEnv</a> :: <a href="Foreign-ForeignPtr-Safe.html#t:FinalizerEnvPtr">FinalizerEnvPtr</a> env a -> <a href="Foreign-Ptr.html#t:Ptr">Ptr</a> env -> <a href="Foreign-ForeignPtr-Safe.html#t:ForeignPtr">ForeignPtr</a> a -> <a href="System-IO.html#t:IO">IO</a> <a href="../ghc-prim-0.2.0.0/GHC-Tuple.html#t:-40--41-">()</a></li><li class="src short"><a href="#v:withForeignPtr">withForeignPtr</a> :: <a href="Foreign-ForeignPtr-Safe.html#t:ForeignPtr">ForeignPtr</a> a -> (<a href="Foreign-Ptr.html#t:Ptr">Ptr</a> a -> <a href="System-IO.html#t:IO">IO</a> b) -> <a href="System-IO.html#t:IO">IO</a> b</li><li class="src short"><a href="#v:finalizeForeignPtr">finalizeForeignPtr</a> :: <a href="Foreign-ForeignPtr-Safe.html#t:ForeignPtr">ForeignPtr</a> a -> <a href="System-IO.html#t:IO">IO</a> <a href="../ghc-prim-0.2.0.0/GHC-Tuple.html#t:-40--41-">()</a></li><li class="src short"><a href="#v:touchForeignPtr">touchForeignPtr</a> :: <a href="Foreign-ForeignPtr-Safe.html#t:ForeignPtr">ForeignPtr</a> a -> <a href="System-IO.html#t:IO">IO</a> <a href="../ghc-prim-0.2.0.0/GHC-Tuple.html#t:-40--41-">()</a></li><li class="src short"><a href="#v:castForeignPtr">castForeignPtr</a> :: <a href="Foreign-ForeignPtr-Safe.html#t:ForeignPtr">ForeignPtr</a> a -> <a href="Foreign-ForeignPtr-Safe.html#t:ForeignPtr">ForeignPtr</a> b</li><li class="src short"><a href="#v:mallocForeignPtr">mallocForeignPtr</a> :: <a href="Foreign-Storable.html#t:Storable">Storable</a> a => <a href="System-IO.html#t:IO">IO</a> (<a href="Foreign-ForeignPtr-Safe.html#t:ForeignPtr">ForeignPtr</a> a)</li><li class="src short"><a href="#v:mallocForeignPtrBytes">mallocForeignPtrBytes</a> :: <a href="Data-Int.html#t:Int">Int</a> -> <a href="System-IO.html#t:IO">IO</a> (<a href="Foreign-ForeignPtr-Safe.html#t:ForeignPtr">ForeignPtr</a> a)</li><li class="src short"><a href="#v:mallocForeignPtrArray">mallocForeignPtrArray</a> :: <a href="Foreign-Storable.html#t:Storable">Storable</a> a => <a href="Data-Int.html#t:Int">Int</a> -> <a href="System-IO.html#t:IO">IO</a> (<a href="Foreign-ForeignPtr-Safe.html#t:ForeignPtr">ForeignPtr</a> a)</li><li class="src short"><a href="#v:mallocForeignPtrArray0">mallocForeignPtrArray0</a> :: <a href="Foreign-Storable.html#t:Storable">Storable</a> a => <a href="Data-Int.html#t:Int">Int</a> -> <a href="System-IO.html#t:IO">IO</a> (<a href="Foreign-ForeignPtr-Safe.html#t:ForeignPtr">ForeignPtr</a> a)</li></ul></div><div id="interface"><h1 id="g:1">Finalised data pointers
</h1><div class="top"><p class="src"><span class="keyword">data</span> <a name="t:ForeignPtr" class="def">ForeignPtr</a> a </p><div class="doc"><p>The type <code><a href="Foreign-ForeignPtr-Safe.html#t:ForeignPtr">ForeignPtr</a></code> represents references to objects that are
maintained in a foreign language, i.e., that are not part of the
data structures usually managed by the Haskell storage manager.
The essential difference between <code><a href="Foreign-ForeignPtr-Safe.html#t:ForeignPtr">ForeignPtr</a></code>s and vanilla memory
references of type <code>Ptr a</code> is that the former may be associated
with <em>finalizers</em>. A finalizer is a routine that is invoked when
the Haskell storage manager detects that - within the Haskell heap
and stack - there are no more references left that are pointing to
the <code><a href="Foreign-ForeignPtr-Safe.html#t:ForeignPtr">ForeignPtr</a></code>. Typically, the finalizer will, then, invoke
routines in the foreign language that free the resources bound by
the foreign object.
</p><p>The <code><a href="Foreign-ForeignPtr-Safe.html#t:ForeignPtr">ForeignPtr</a></code> is parameterised in the same way as <code><a href="Foreign-Ptr.html#t:Ptr">Ptr</a></code>. The
type argument of <code><a href="Foreign-ForeignPtr-Safe.html#t:ForeignPtr">ForeignPtr</a></code> should normally be an instance of
class <code><a href="Foreign-Storable.html#t:Storable">Storable</a></code>.
</p></div><div class="subs instances"><p id="control.i:ForeignPtr" class="caption collapser" onclick="toggleSection('i:ForeignPtr')">Instances</p><div id="section.i:ForeignPtr" class="show"><table><tr><td class="src"><a href="Data-Typeable-Internal.html#t:Typeable1">Typeable1</a> <a href="Foreign-ForeignPtr-Safe.html#t:ForeignPtr">ForeignPtr</a></td><td class="doc empty"> </td></tr><tr><td class="src"><a href="Data-Eq.html#t:Eq">Eq</a> (<a href="Foreign-ForeignPtr-Safe.html#t:ForeignPtr">ForeignPtr</a> a)</td><td class="doc empty"> </td></tr><tr><td class="src"><a href="Data-Typeable-Internal.html#t:Typeable">Typeable</a> a => <a href="Data-Data.html#t:Data">Data</a> (<a href="Foreign-ForeignPtr-Safe.html#t:ForeignPtr">ForeignPtr</a> a)</td><td class="doc empty"> </td></tr><tr><td class="src"><a href="Data-Ord.html#t:Ord">Ord</a> (<a href="Foreign-ForeignPtr-Safe.html#t:ForeignPtr">ForeignPtr</a> a)</td><td class="doc empty"> </td></tr><tr><td class="src"><a href="Text-Show.html#t:Show">Show</a> (<a href="Foreign-ForeignPtr-Safe.html#t:ForeignPtr">ForeignPtr</a> a)</td><td class="doc empty"> </td></tr></table></div></div></div><div class="top"><p class="src"><span class="keyword">type</span> <a name="t:FinalizerPtr" class="def">FinalizerPtr</a> a = <a href="Foreign-Ptr.html#t:FunPtr">FunPtr</a> (<a href="Foreign-Ptr.html#t:Ptr">Ptr</a> a -> <a href="System-IO.html#t:IO">IO</a> <a href="../ghc-prim-0.2.0.0/GHC-Tuple.html#t:-40--41-">()</a>)</p><div class="doc"><p>A finalizer is represented as a pointer to a foreign function that, at
finalisation time, gets as an argument a plain pointer variant of the
foreign pointer that the finalizer is associated with.
</p></div></div><div class="top"><p class="src"><span class="keyword">type</span> <a name="t:FinalizerEnvPtr" class="def">FinalizerEnvPtr</a> env a = <a href="Foreign-Ptr.html#t:FunPtr">FunPtr</a> (<a href="Foreign-Ptr.html#t:Ptr">Ptr</a> env -> <a href="Foreign-Ptr.html#t:Ptr">Ptr</a> a -> <a href="System-IO.html#t:IO">IO</a> <a href="../ghc-prim-0.2.0.0/GHC-Tuple.html#t:-40--41-">()</a>)</p></div><h2 id="g:2">Basic operations
</h2><div class="top"><p class="src"><a name="v:newForeignPtr" class="def">newForeignPtr</a> :: <a href="Foreign-ForeignPtr-Safe.html#t:FinalizerPtr">FinalizerPtr</a> a -> <a href="Foreign-Ptr.html#t:Ptr">Ptr</a> a -> <a href="System-IO.html#t:IO">IO</a> (<a href="Foreign-ForeignPtr-Safe.html#t:ForeignPtr">ForeignPtr</a> a)</p><div class="doc"><p>Turns a plain memory reference into a foreign pointer, and
associates a finalizer with the reference. The finalizer will be
executed after the last reference to the foreign object is dropped.
There is no guarantee of promptness, however the finalizer will be
executed before the program exits.
</p></div></div><div class="top"><p class="src"><a name="v:newForeignPtr_" class="def">newForeignPtr_</a> :: <a href="Foreign-Ptr.html#t:Ptr">Ptr</a> a -> <a href="System-IO.html#t:IO">IO</a> (<a href="Foreign-ForeignPtr-Safe.html#t:ForeignPtr">ForeignPtr</a> a)</p><div class="doc"><p>Turns a plain memory reference into a foreign pointer that may be
associated with finalizers by using <code><a href="Foreign-ForeignPtr-Safe.html#v:addForeignPtrFinalizer">addForeignPtrFinalizer</a></code>.
</p></div></div><div class="top"><p class="src"><a name="v:addForeignPtrFinalizer" class="def">addForeignPtrFinalizer</a> :: <a href="Foreign-ForeignPtr-Safe.html#t:FinalizerPtr">FinalizerPtr</a> a -> <a href="Foreign-ForeignPtr-Safe.html#t:ForeignPtr">ForeignPtr</a> a -> <a href="System-IO.html#t:IO">IO</a> <a href="../ghc-prim-0.2.0.0/GHC-Tuple.html#t:-40--41-">()</a></p><div class="doc"><p>This function adds a finalizer to the given foreign object. The
finalizer will run <em>before</em> all other finalizers for the same
object which have already been registered.
</p></div></div><div class="top"><p class="src"><a name="v:newForeignPtrEnv" class="def">newForeignPtrEnv</a> :: <a href="Foreign-ForeignPtr-Safe.html#t:FinalizerEnvPtr">FinalizerEnvPtr</a> env a -> <a href="Foreign-Ptr.html#t:Ptr">Ptr</a> env -> <a href="Foreign-Ptr.html#t:Ptr">Ptr</a> a -> <a href="System-IO.html#t:IO">IO</a> (<a href="Foreign-ForeignPtr-Safe.html#t:ForeignPtr">ForeignPtr</a> a)</p><div class="doc"><p>This variant of <code><a href="Foreign-ForeignPtr-Safe.html#v:newForeignPtr">newForeignPtr</a></code> adds a finalizer that expects an
environment in addition to the finalized pointer. The environment
that will be passed to the finalizer is fixed by the second argument to
<code><a href="Foreign-ForeignPtr-Safe.html#v:newForeignPtrEnv">newForeignPtrEnv</a></code>.
</p></div></div><div class="top"><p class="src"><a name="v:addForeignPtrFinalizerEnv" class="def">addForeignPtrFinalizerEnv</a> :: <a href="Foreign-ForeignPtr-Safe.html#t:FinalizerEnvPtr">FinalizerEnvPtr</a> env a -> <a href="Foreign-Ptr.html#t:Ptr">Ptr</a> env -> <a href="Foreign-ForeignPtr-Safe.html#t:ForeignPtr">ForeignPtr</a> a -> <a href="System-IO.html#t:IO">IO</a> <a href="../ghc-prim-0.2.0.0/GHC-Tuple.html#t:-40--41-">()</a></p><div class="doc"><p>Like <code><a href="Foreign-ForeignPtr-Safe.html#v:addForeignPtrFinalizerEnv">addForeignPtrFinalizerEnv</a></code> but allows the finalizer to be
passed an additional environment parameter to be passed to the
finalizer. The environment passed to the finalizer is fixed by the
second argument to <code><a href="Foreign-ForeignPtr-Safe.html#v:addForeignPtrFinalizerEnv">addForeignPtrFinalizerEnv</a></code>
</p></div></div><div class="top"><p class="src"><a name="v:withForeignPtr" class="def">withForeignPtr</a> :: <a href="Foreign-ForeignPtr-Safe.html#t:ForeignPtr">ForeignPtr</a> a -> (<a href="Foreign-Ptr.html#t:Ptr">Ptr</a> a -> <a href="System-IO.html#t:IO">IO</a> b) -> <a href="System-IO.html#t:IO">IO</a> b</p><div class="doc"><p>This is a way to look at the pointer living inside a
foreign object. This function takes a function which is
applied to that pointer. The resulting <code><a href="System-IO.html#t:IO">IO</a></code> action is then
executed. The foreign object is kept alive at least during
the whole action, even if it is not used directly
inside. Note that it is not safe to return the pointer from
the action and use it after the action completes. All uses
of the pointer should be inside the
<code><a href="Foreign-ForeignPtr-Safe.html#v:withForeignPtr">withForeignPtr</a></code> bracket. The reason for
this unsafeness is the same as for
<code><a href="Foreign-ForeignPtr-Unsafe.html#v:unsafeForeignPtrToPtr">unsafeForeignPtrToPtr</a></code> below: the finalizer
may run earlier than expected, because the compiler can only
track usage of the <code><a href="Foreign-ForeignPtr-Safe.html#t:ForeignPtr">ForeignPtr</a></code> object, not
a <code><a href="Foreign-Ptr.html#t:Ptr">Ptr</a></code> object made from it.
</p><p>This function is normally used for marshalling data to
or from the object pointed to by the
<code><a href="Foreign-ForeignPtr-Safe.html#t:ForeignPtr">ForeignPtr</a></code>, using the operations from the
<code><a href="Foreign-Storable.html#t:Storable">Storable</a></code> class.
</p></div></div><div class="top"><p class="src"><a name="v:finalizeForeignPtr" class="def">finalizeForeignPtr</a> :: <a href="Foreign-ForeignPtr-Safe.html#t:ForeignPtr">ForeignPtr</a> a -> <a href="System-IO.html#t:IO">IO</a> <a href="../ghc-prim-0.2.0.0/GHC-Tuple.html#t:-40--41-">()</a></p><div class="doc"><p>Causes the finalizers associated with a foreign pointer to be run
immediately.
</p></div></div><h2 id="g:3">Low-level operations
</h2><div class="top"><p class="src"><a name="v:touchForeignPtr" class="def">touchForeignPtr</a> :: <a href="Foreign-ForeignPtr-Safe.html#t:ForeignPtr">ForeignPtr</a> a -> <a href="System-IO.html#t:IO">IO</a> <a href="../ghc-prim-0.2.0.0/GHC-Tuple.html#t:-40--41-">()</a></p><div class="doc"><p>This function ensures that the foreign object in
question is alive at the given place in the sequence of IO
actions. In particular <code><a href="Foreign-ForeignPtr.html#v:withForeignPtr">withForeignPtr</a></code>
does a <code><a href="Foreign-ForeignPtr-Safe.html#v:touchForeignPtr">touchForeignPtr</a></code> after it
executes the user action.
</p><p>Note that this function should not be used to express dependencies
between finalizers on <code><a href="Foreign-ForeignPtr-Safe.html#t:ForeignPtr">ForeignPtr</a></code>s. For example, if the finalizer
for a <code><a href="Foreign-ForeignPtr-Safe.html#t:ForeignPtr">ForeignPtr</a></code> <code>F1</code> calls <code><a href="Foreign-ForeignPtr-Safe.html#v:touchForeignPtr">touchForeignPtr</a></code> on a second
<code><a href="Foreign-ForeignPtr-Safe.html#t:ForeignPtr">ForeignPtr</a></code> <code>F2</code>, then the only guarantee is that the finalizer
for <code>F2</code> is never started before the finalizer for <code>F1</code>. They
might be started together if for example both <code>F1</code> and <code>F2</code> are
otherwise unreachable, and in that case the scheduler might end up
running the finalizer for <code>F2</code> first.
</p><p>In general, it is not recommended to use finalizers on separate
objects with ordering constraints between them. To express the
ordering robustly requires explicit synchronisation using <code>MVar</code>s
between the finalizers, but even then the runtime sometimes runs
multiple finalizers sequentially in a single thread (for
performance reasons), so synchronisation between finalizers could
result in artificial deadlock. Another alternative is to use
explicit reference counting.
</p></div></div><div class="top"><p class="src"><a name="v:castForeignPtr" class="def">castForeignPtr</a> :: <a href="Foreign-ForeignPtr-Safe.html#t:ForeignPtr">ForeignPtr</a> a -> <a href="Foreign-ForeignPtr-Safe.html#t:ForeignPtr">ForeignPtr</a> b</p><div class="doc"><p>This function casts a <code><a href="Foreign-ForeignPtr-Safe.html#t:ForeignPtr">ForeignPtr</a></code>
parameterised by one type into another type.
</p></div></div><h2 id="g:4">Allocating managed memory
</h2><div class="top"><p class="src"><a name="v:mallocForeignPtr" class="def">mallocForeignPtr</a> :: <a href="Foreign-Storable.html#t:Storable">Storable</a> a => <a href="System-IO.html#t:IO">IO</a> (<a href="Foreign-ForeignPtr-Safe.html#t:ForeignPtr">ForeignPtr</a> a)</p><div class="doc"><p>Allocate some memory and return a <code><a href="Foreign-ForeignPtr-Safe.html#t:ForeignPtr">ForeignPtr</a></code> to it. The memory
will be released automatically when the <code><a href="Foreign-ForeignPtr-Safe.html#t:ForeignPtr">ForeignPtr</a></code> is discarded.
</p><p><code><a href="Foreign-ForeignPtr-Safe.html#v:mallocForeignPtr">mallocForeignPtr</a></code> is equivalent to
</p><pre> do { p <- malloc; newForeignPtr finalizerFree p }
</pre><p>although it may be implemented differently internally: you may not
assume that the memory returned by <code><a href="Foreign-ForeignPtr-Safe.html#v:mallocForeignPtr">mallocForeignPtr</a></code> has been
allocated with <code><a href="Foreign-Marshal-Alloc.html#v:malloc">malloc</a></code>.
</p><p>GHC notes: <code><a href="Foreign-ForeignPtr-Safe.html#v:mallocForeignPtr">mallocForeignPtr</a></code> has a heavily optimised
implementation in GHC. It uses pinned memory in the garbage
collected heap, so the <code><a href="Foreign-ForeignPtr-Safe.html#t:ForeignPtr">ForeignPtr</a></code> does not require a finalizer to
free the memory. Use of <code><a href="Foreign-ForeignPtr-Safe.html#v:mallocForeignPtr">mallocForeignPtr</a></code> and associated
functions is strongly recommended in preference to <code>newForeignPtr</code>
with a finalizer.
</p></div></div><div class="top"><p class="src"><a name="v:mallocForeignPtrBytes" class="def">mallocForeignPtrBytes</a> :: <a href="Data-Int.html#t:Int">Int</a> -> <a href="System-IO.html#t:IO">IO</a> (<a href="Foreign-ForeignPtr-Safe.html#t:ForeignPtr">ForeignPtr</a> a)</p><div class="doc"><p>This function is similar to <code><a href="Foreign-ForeignPtr-Safe.html#v:mallocForeignPtr">mallocForeignPtr</a></code>, except that the
size of the memory required is given explicitly as a number of bytes.
</p></div></div><div class="top"><p class="src"><a name="v:mallocForeignPtrArray" class="def">mallocForeignPtrArray</a> :: <a href="Foreign-Storable.html#t:Storable">Storable</a> a => <a href="Data-Int.html#t:Int">Int</a> -> <a href="System-IO.html#t:IO">IO</a> (<a href="Foreign-ForeignPtr-Safe.html#t:ForeignPtr">ForeignPtr</a> a)</p><div class="doc"><p>This function is similar to <code><a href="Foreign-Marshal-Array.html#v:mallocArray">mallocArray</a></code>,
but yields a memory area that has a finalizer attached that releases
the memory area. As with <code><a href="Foreign-ForeignPtr-Safe.html#v:mallocForeignPtr">mallocForeignPtr</a></code>, it is not guaranteed that
the block of memory was allocated by <code><a href="Foreign-Marshal-Alloc.html#v:malloc">malloc</a></code>.
</p></div></div><div class="top"><p class="src"><a name="v:mallocForeignPtrArray0" class="def">mallocForeignPtrArray0</a> :: <a href="Foreign-Storable.html#t:Storable">Storable</a> a => <a href="Data-Int.html#t:Int">Int</a> -> <a href="System-IO.html#t:IO">IO</a> (<a href="Foreign-ForeignPtr-Safe.html#t:ForeignPtr">ForeignPtr</a> a)</p><div class="doc"><p>This function is similar to <code><a href="Foreign-Marshal-Array.html#v:mallocArray0">mallocArray0</a></code>,
but yields a memory area that has a finalizer attached that releases
the memory area. As with <code><a href="Foreign-ForeignPtr-Safe.html#v:mallocForeignPtr">mallocForeignPtr</a></code>, it is not guaranteed that
the block of memory was allocated by <code><a href="Foreign-Marshal-Alloc.html#v:malloc">malloc</a></code>.
</p></div></div></div></div><div id="footer"><p>Produced by <a href="http://www.haskell.org/haddock/">Haddock</a> version 2.11.0</p></div></body></html>
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