<listitem>
<para><constant>:char</constant> - Signed 8-bits. A
dereferenced :char pointer returns an character.</para>
-</para>
</listitem>
<listitem>
<para><constant>:unsigned-char</constant> - Unsigned 8-bits. A dereferenced :unsigned-char
pointer returns an character.</para>
</listitem>
<listitem>
- <listitem>
- <para><constant>:byte</constant> - Unsigned 8-bits. A
+ <para><constant>:byte</constant> - Signed 8-bits. A
dereferenced :byte pointer returns an integer.</para>
+ </listitem>
+ <listitem>
+ <para><constant>:unsigned-byte</constant> - Unsigned 8-bits. A
+dereferenced :unsigned-byte pointer returns an integer.</para>
</listitem>
<listitem>
<para><constant>:short</constant> - Signed 16-bits.</para>
<refsect1>
<title>Examples</title>
<programlisting>
-(def-array ca :char)
+(def-array-pointer ca :unsigned-char)
(let ((fs (convert-to-foreign-string "ab")))
(values (null-char-p (deref-array fs 'ca 0))
(null-char-p (deref-array fs 'ca 2))))
<refentry id="get-slot-value">
<refnamediv>
- <refname>def-slot-value</refname>
+ <refname>get-slot-value</refname>
<refpurpose>Retrieves a value from a slot of a structure.
</refpurpose>
<refclass>Macro</refclass>
</refentry>
- <refentry id="def-array">
+ <refentry id="def-array-pointer">
<refnamediv>
- <refname>def-array</refname>
- <refpurpose>Defines a foreign array type.
+ <refname>def-array-pointer</refname>
+ <refpurpose>Defines a pointer to a array of type.
</refpurpose>
<refclass>Macro</refclass>
</refnamediv>
<refsynopsisdiv>
<title>Syntax</title>
<synopsis>
- <function>def-array</function> <replaceable>name type</replaceable>
+ <function>def-array-pointer</function> <replaceable>name type</replaceable>
</synopsis>
</refsynopsisdiv>
<refsect1>
<refsect1>
<title>Description</title>
<para>
- Defines a foreign array type.
+ Defines a type tat is a pointer to an array of type.
</para>
</refsect1>
<refsect1>
<title>Examples</title>
<programlisting>
-(def-array byte-array :unsigned-char)
+(def-array-pointer byte-array-pointer :unsigned-char)
</programlisting>
</refsect1>
<refsect1>
<para>None.</para>
</refsect1>
</refentry>
+
+ <refentry id="def-union">
+ <refnamediv>
+ <refname>def-union</refname>
+ <refpurpose>Defines a foreign union type.
+ </refpurpose>
+ <refclass>Macro</refclass>
+ </refnamediv>
+ <refsynopsisdiv>
+ <title>Syntax</title>
+ <synopsis>
+ <function>def-union</function> <replaceable>name &rest fields</replaceable>
+ </synopsis>
+ </refsynopsisdiv>
+ <refsect1>
+ <title>Arguments and Values</title>
+ <variablelist>
+ <varlistentry>
+ <term><parameter>name</parameter></term>
+ <listitem>
+ <para>A name of the new union type.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><parameter>fields</parameter></term>
+ <listitem>
+ <para>A list of fields of the union.
+ </para>
+ </listitem>
+ </varlistentry>
+ </variablelist>
+ </refsect1>
+ <refsect1>
+ <title>Description</title>
+ <para>
+ Defines a foreign union type.
+ </para>
+ </refsect1>
+ <refsect1>
+ <title>Examples</title>
+ <programlisting>
+(def-union test-union
+ (a-char :char)
+ (an-int :int))
+
+(let ((u (allocate-foreign-object 'test-union))
+ (setf (get-slot-value u 'test-union 'an-int) (+ 65 (* 66 256)))
+ (prog1
+ (ensure-char-character (get-slot-value u 'test-union 'a-char))
+ (free-foreign-object u)))
+=> #\A
+ </programlisting>
+ </refsect1>
+ <refsect1>
+ <title>Side Effects</title>
+ <para>Defines a new foreign type.</para>
+ </refsect1>
+ <refsect1>
+ <title>Affected by</title>
+ <para>None.</para>
+ </refsect1>
+ <refsect1>
+ <title>Exceptional Situations</title>
+ <para>None.</para>
+ </refsect1>
+ </refentry>
+
+
</reference>
<reference>
<partintro>
<title>Overview</title>
<para>
- Objects are entities that can allocated and freed.
+ Objects are entities that can allocated, referred to by pointers, and
+can be freed.
</para>
</partintro>
<refsynopsisdiv>
<title>Syntax</title>
<synopsis>
- <function>allocate-foreign-object</function> <replaceable>type</replaceable> => <returnvalue>ptr</returnvalue>
+ <function>allocate-foreign-object</function> <replaceable>type &optional size</replaceable> => <returnvalue>ptr</returnvalue>
</synopsis>
</refsynopsisdiv>
<refsect1>
<varlistentry>
<term><parameter>type</parameter></term>
<listitem>
- <para>A type of foreign object to allocate.
+ <para>The type of foreign object to allocate. This parameter is evaluated.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><parameter>size</parameter></term>
+ <listitem>
+ <para>An optional size parameter that is evaluated. If specified, allocates and returns an
+array of <parameter>type</parameter> that is <parameter>size</parameter> members long. This parameter is evaluated.
</para>
</listitem>
</varlistentry>
</refentry>
+ <refentry id="with-foreign-object">
+ <refnamediv>
+ <refname>with-foreign-object</refname>
+ <refpurpose>Wraps the allocation of a foreign object around a body of code.
+ </refpurpose>
+ <refclass>Macro</refclass>
+ </refnamediv>
+ <refsynopsisdiv>
+ <title>Syntax</title>
+ <synopsis>
+ <function>with-foreign-object</function> <replaceable>(var type) &body body</replaceable> => <returnvalue>form-return</returnvalue>
+ </synopsis>
+ </refsynopsisdiv>
+ <refsect1>
+ <title>Arguments and Values</title>
+ <variablelist>
+ <varlistentry>
+ <term><parameter>var</parameter></term>
+ <listitem>
+ <para>The variable name to bind.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><parameter>type</parameter></term>
+ <listitem>
+ <para>The type of foreign object to allocate. This parameter is evaluated.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><returnvalue>form-return</returnvalue></term>
+ <listitem>
+ <para>The result of evaluating the <parameter>body</parameter>.
+ </para>
+ </listitem>
+ </varlistentry>
+ </variablelist>
+ </refsect1>
+ <refsect1>
+ <title>Description</title>
+ <para>
+This function wraps the allocation, binding, and destruction of a foreign object.
+On &cmucl; and
+&lw; platforms the object is stack allocated for efficiency. Benchmarks show that &acl; performs
+much better with static allocation.
+ </para>
+ </refsect1>
+ <refsect1>
+ <title>Examples</title>
+ <programlisting>
+(defun gethostname2 ()
+ "Returns the hostname"
+ (uffi:with-foreign-object (name '(:array :unsigned-char 256))
+ (if (zerop (c-gethostname (uffi:char-array-to-pointer name) 256))
+ (uffi:convert-from-foreign-string name)
+ (error "gethostname() failed."))))
+ </programlisting>
+ </refsect1>
+ <refsect1>
+ <title>Side Effects</title>
+ <para>None.</para>
+ </refsect1>
+ <refsect1>
+ <title>Affected by</title>
+ <para>None.</para>
+ </refsect1>
+ <refsect1>
+ <title>Exceptional Situations</title>
+ <para>None.</para>
+ </refsect1>
+ </refentry>
+
+ <refentry id="size-of-foreign-type">
+ <refnamediv>
+ <refname>size-of-foreign-type</refname>
+ <refpurpose>Returns the number of data bytes used by a foreign object type.
+ </refpurpose>
+ <refclass>Macro</refclass>
+ </refnamediv>
+ <refsynopsisdiv>
+ <title>Syntax</title>
+ <synopsis>
+ <function>size-of-foreign-type</function> <replaceable>ftype</replaceable>
+ </synopsis>
+ </refsynopsisdiv>
+ <refsect1>
+ <title>Arguments and Values</title>
+ <variablelist>
+ <varlistentry>
+ <term><parameter>ftype</parameter></term>
+ <listitem>
+ <para>A foreign type specifier. This parameter is evaluated.
+ </para>
+ </listitem>
+ </varlistentry>
+ </variablelist>
+ </refsect1>
+ <refsect1>
+ <title>Description</title>
+ <para>
+ Returns the number of data bytes used by a foreign object type. This does not include any Lisp storage overhead.
+ </para>
+ </refsect1>
+ <refsect1>
+ <title>Examples</title>
+ <para>
+<programlisting>
+(size-of-foreign-object :unsigned-byte)
+=> 1
+(size-of-foreign-object 'my-100-byte-vector-type)
+=> 100
+</programlisting>
+ </para>
+ </refsect1>
+ <refsect1>
+ <title>Side Effects</title>
+ <para>None.</para>
+ </refsect1> <refsect1>
+ <title>Affected by</title>
+ <para>None.</para>
+ </refsect1>
+ <refsect1>
+ <title>Exceptional Situations</title>
+ <para>None.</para>
+ </refsect1>
+ </refentry>
+
<refentry id="pointer-address">
<refnamediv>
<refname>pointer-address</refname>
<refsynopsisdiv>
<title>Syntax</title>
<synopsis>
- <function>def-pointer</function> <replaceable>ptr type</replaceable> => <returnvalue>value</returnvalue>
+ <function>deref-pointer</function> <replaceable>ptr type</replaceable> => <returnvalue>value</returnvalue>
</synopsis>
</refsynopsisdiv>
<refsect1>
</listitem>
</varlistentry>
<varlistentry>
- <term><parameter>value</parameter></term>
+ <term><returnvalue>value</returnvalue></term>
<listitem>
<para>The value of the object where the pointer points.
</para>
<title>Examples</title>
<para>
<programlisting>
+(let ((intp (allocate-foreign-object :int)))
+ (setf (deref-pointer intp :int) 10)
+ (prog1
+ (deref-pointer intp :int)
+ (free-foreign-object intp)))
+=> 10
+</programlisting>
+ </para>
+ </refsect1>
+ <refsect1>
+ <title>Side Effects</title>
+ <para>None.</para>
+ </refsect1>
+ <refsect1>
+ <title>Affected by</title>
+ <para>None.</para>
+ </refsect1>
+ <refsect1>
+ <title>Exceptional Situations</title>
+ <para>None.</para>
+ </refsect1>
+ </refentry>
+
+ <refentry id="ensure-char-character">
+ <refnamediv>
+ <refname>ensure-char-character</refname>
+ <refpurpose>Ensures that a dereferenced <constant>:char</constant> pointer is
+a character.
+ </refpurpose>
+ <refclass>Macro</refclass>
+ </refnamediv>
+ <refsynopsisdiv>
+ <title>Syntax</title>
+ <synopsis>
+ <function>ensure-char-character</function> <replaceable>object</replaceable> => <returnvalue>char</returnvalue>
+ </synopsis>
+ </refsynopsisdiv>
+ <refsect1>
+ <title>Arguments and Values</title>
+ <variablelist>
+ <varlistentry>
+ <term><parameter>object</parameter></term>
+ <listitem>
+ <para>Either a character or a integer specifying a character code.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><returnvalue>char</returnvalue></term>
+ <listitem>
+ <para>A character.
+ </para>
+ </listitem>
+ </varlistentry>
+ </variablelist>
+ </refsect1>
+ <refsect1>
+ <title>Description</title>
+ <para>
+ Ensures that an object obtained by dereferencing a
+<constant>:char</constant> pointer is a character.
+ </para>
+ </refsect1>
+ <refsect1>
+ <title>Examples</title>
+ <para>
+<programlisting>
(let ((fs (convert-to-foreign-string "a")))
(prog1
- (ensure-char (deref-pointer fs :char))
+ (ensure-char-character (deref-pointer fs :char))
(free-foreign-object fs)))
=> #\a
</programlisting>
</refsect1>
<refsect1>
<title>Exceptional Situations</title>
+ <para>Depending upon the implementation and what &uffi; expects, this
+macro may signal an error if the object is not a character or
+integer.</para>
+ </refsect1>
+ </refentry>
+
+ <refentry id="ensure-char-integer">
+ <refnamediv>
+ <refname>ensure-char-integer</refname>
+ <refpurpose>Ensures that a dereferenced <constant>:char</constant> pointer is
+an integer.
+ </refpurpose>
+ <refclass>Macro</refclass>
+ </refnamediv>
+ <refsynopsisdiv>
+ <title>Syntax</title>
+ <synopsis>
+ <function>ensure-char-integer</function> <replaceable>object</replaceable> => <returnvalue>int</returnvalue>
+ </synopsis>
+ </refsynopsisdiv>
+ <refsect1>
+ <title>Arguments and Values</title>
+ <variablelist>
+ <varlistentry>
+ <term><parameter>object</parameter></term>
+ <listitem>
+ <para>Either a character or a integer specifying a character code.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><returnvalue>int</returnvalue></term>
+ <listitem>
+ <para>An integer.
+ </para>
+ </listitem>
+ </varlistentry>
+ </variablelist>
+ </refsect1>
+ <refsect1>
+ <title>Description</title>
+ <para>
+ Ensures that an object obtained by dereferencing a
+<constant>:char</constant> pointer is an integer.
+ </para>
+ </refsect1>
+ <refsect1>
+ <title>Examples</title>
+ <para>
+<programlisting>
+(let ((fs (convert-to-foreign-string "a")))
+ (prog1
+ (ensure-char-integer (deref-pointer fs :char))
+ (free-foreign-object fs)))
+=> 96
+</programlisting>
+ </para>
+ </refsect1>
+ <refsect1>
+ <title>Side Effects</title>
+ <para>None.</para>
+ </refsect1>
+ <refsect1>
+ <title>Affected by</title>
<para>None.</para>
</refsect1>
+ <refsect1>
+ <title>Exceptional Situations</title>
+ <para>Depending upon the implementation and what &uffi; expects, this
+macro may signal an error if the object is not a character or
+integer.</para>
+ </refsect1>
</refentry>
<refentry id="make-null-pointer">
<partintro>
<title>Overview</title>
<para>
- &uffi; has functions to two types of <varname>C</varname>-compatible
- strings, <emphasis>cstring</emphasis> and <emphasis>foreign</emphasis> strings.
-cstrings are used as parameters to and from functions. An implementation, such as CMUCL,
-may not convert these to a foreign type for efficiency sake. Thus, it is not
-possible to "allocate" a cstring. In contrast, foreign strings
-always need to have memory for them.
- </para>
+
+ &uffi; has functions to two types of
+<varname>C</varname>-compatible
+ strings: <emphasis>cstring</emphasis> and
+<emphasis>foreign</emphasis> strings.
+
+cstrings are used <emphasis>only</emphasis> as parameters to and from
+functions. In some implementations a cstring is not a foreign type but
+rather the Lisp string itself. On other platforms a cstring is a newly
+allocated foreign vector for storing characters. The following is an
+example of using cstrings to both send and return a value.
+</para>
+
+<programlisting>
+(uffi:def-function ("getenv" c-getenv)
+ ((name :cstring))
+ :returning :cstring)
+
+(defun my-getenv (key)
+ "Returns an environment variable, or NIL if it does not exist"
+ (check-type key string)
+ (uffi:with-cstring (key-native key)
+ (uffi:convert-from-cstring (c-getenv key-native))))
+</programlisting>
+
+<para> In contrast, foreign strings are always a foreign vector of
+characters which have memory allocated. Thus, if you need to allocate
+memory to hold the return value of a string, you must use a foreign
+string and not a cstring. The following is an example of using a foreign
+string for a return value. </para>
+
+<programlisting>
+(uffi:def-function ("gethostname" c-gethostname)
+ ((name (* :unsigned-char))
+ (len :int))
+ :returning :int)
+
+(defun gethostname ()
+ "Returns the hostname"
+ (let* ((name (uffi:allocate-foreign-string 256))
+ (result-code (c-gethostname name 256))
+ (hostname (when (zerop result-code)
+ (uffi:convert-from-foreign-string name))))
+ (uffi:free-foreign-object name)
+ (unless (zerop result-code)
+ (error "gethostname() failed."))))
+</programlisting>
+
</partintro>
<refentry id="convert-from-cstring">
</refsect1>
<refsect1>
<title>Side Effects</title>
- <para>None.</para>
+ <para>On some implementations, this function allocates memory.</para>
</refsect1>
<refsect1>
<title>Affected by</title>
<title>Description</title>
<para>
Frees any memory possibly allocated by
- <function>convert-to-cstring</function>.
+ <function>convert-to-cstring</function>. On some implementions, a cstring is just the Lisp string itself.
</para>
</refsect1>
<refsect1>
<refsect1>
<title>Description</title>
<para>
- Binds a lexical variable to a newly allocated <varname>cstring</varname>. Automatically frees <varname>cstring</varname>.
+ Binds a symbol to a cstring created from conversion of a string. Automatically frees the <varname>cstring</varname>.
</para>
</refsect1>
<refsect1>
<title>Examples</title>
<programlisting>
(def-function "gethostname"
- ((name :cstring)
+ ((name (* :unsigned-char))
(len :int))
:returning :int)
</programlisting>
</refsect1>
</refentry>
+ <refentry id="find-foreign-library">
+ <refnamediv>
+ <refname>find-foreign-library</refname>
+ <refpurpose>Finds a foreign library file.
+ </refpurpose>
+ <refclass>Function</refclass>
+ </refnamediv>
+ <refsect1>
+ <title>Syntax</title>
+<synopsis>
+ <function>find-foreign-library</function> <replaceable>names directories & drive-letters types</replaceable> => <returnvalue>path</returnvalue>
+</synopsis>
+ </refsect1>
+ <refsect1>
+ <title>Arguments and Values</title>
+ <variablelist>
+ <varlistentry>
+ <term><parameter>names</parameter></term>
+ <listitem>
+ <para>A string or list of strings containing the base name of the library file.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><parameter>directories</parameter></term>
+ <listitem>
+ <para>A string or list of strings containing the directory the library file.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><parameter>drive-letters</parameter></term>
+ <listitem>
+ <para>A string or list of strings containing the drive letters for the library file.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><parameter>types</parameter></term>
+ <listitem>
+ <para>A string or list of strings containing the file type of the library file. Default
+is &nil;. If &nil;, will use a default type based on the currently running implementation.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><returnvalue>path</returnvalue></term>
+ <listitem>
+ <para>A path containing the path found, or &nil; if the library file was not found.
+ </para>
+ </listitem>
+ </varlistentry>
+ </variablelist>
+ </refsect1>
+ <refsect1>
+ <title>Description</title>
+ <para>Finds a foreign library by searching through a number of possible locations. Returns
+the path of the first found file.
+ </para>
+ </refsect1>
+ <refsect1>
+ <title>Examples</title>
+ <programlisting>
+(find-foreign-library '("libmysqlclient" "libmysql")
+ '("/opt/mysql/lib/mysql/" "/usr/local/lib/" "/usr/lib/" "/mysql/lib/opt/")
+ :types '("so" "dll")
+ :drive-letters '("C" "D" "E"))
+=> #P"D:\\mysql\\lib\\opt\\libmysql.dll"
+ </programlisting>
+ </refsect1>
+ <refsect1>
+ <title>Side Effects</title>
+ <para>None.
+ </para>
+ </refsect1>
+ <refsect1>
+ <title>Affected by</title>
+ <para>None.</para>
+ </refsect1>
+ <refsect1>
+ <title>Exceptional Situations</title>
+ <para>None.</para>
+ </refsect1>
+ </refentry>
+
</reference>