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| author | sanine <sanine.not@pm.me> | 2023-03-11 15:58:20 -0600 |
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| committer | sanine <sanine.not@pm.me> | 2023-03-11 15:58:20 -0600 |
| commit | ebc50b387ab209c9f9a0d92e340ac293d5697274 (patch) | |
| tree | ea8c8b3677a18c994d2b9d33dbef3461dcf18113 /libs/luajit-cmake/luajit/doc/ext_ffi_api.html | |
| parent | c2329b4c8258baa9429c77566c9def97d00e96d7 (diff) | |
build & link with luajit instead of lua5.1
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diff --git a/libs/luajit-cmake/luajit/doc/ext_ffi_api.html b/libs/luajit-cmake/luajit/doc/ext_ffi_api.html new file mode 100644 index 0000000..89ddb0d --- /dev/null +++ b/libs/luajit-cmake/luajit/doc/ext_ffi_api.html @@ -0,0 +1,566 @@ +<!DOCTYPE html> +<html> +<head> +<title>ffi.* API Functions</title> +<meta charset="utf-8"> +<meta name="Copyright" content="Copyright (C) 2005-2022"> +<meta name="Language" content="en"> +<link rel="stylesheet" type="text/css" href="bluequad.css" media="screen"> +<link rel="stylesheet" type="text/css" href="bluequad-print.css" media="print"> +<style type="text/css"> +table.abitable { width: 30em; line-height: 1.2; } +tr.abihead td { font-weight: bold; } +td.abiparam { font-weight: bold; width: 6em; } +</style> +</head> +<body> +<div id="site"> +<a href="https://luajit.org"><span>Lua<span id="logo">JIT</span></span></a> +</div> +<div id="head"> +<h1><tt>ffi.*</tt> API Functions</h1> +</div> +<div id="nav"> +<ul><li> +<a href="luajit.html">LuaJIT</a> +<ul><li> +<a href="https://luajit.org/download.html">Download <span class="ext">»</span></a> +</li><li> +<a href="install.html">Installation</a> +</li><li> +<a href="running.html">Running</a> +</li></ul> +</li><li> +<a href="extensions.html">Extensions</a> +<ul><li> +<a href="ext_ffi.html">FFI Library</a> +<ul><li> +<a href="ext_ffi_tutorial.html">FFI Tutorial</a> +</li><li> +<a class="current" href="ext_ffi_api.html">ffi.* API</a> +</li><li> +<a href="ext_ffi_semantics.html">FFI Semantics</a> +</li></ul> +</li><li> +<a href="ext_buffer.html">String Buffers</a> +</li><li> +<a href="ext_jit.html">jit.* Library</a> +</li><li> +<a href="ext_c_api.html">Lua/C API</a> +</li><li> +<a href="ext_profiler.html">Profiler</a> +</li></ul> +</li><li> +<a href="status.html">Status</a> +</li><li> +<a href="faq.html">FAQ</a> +</li><li> +<a href="https://luajit.org/list.html">Mailing List <span class="ext">»</span></a> +</li></ul> +</div> +<div id="main"> +<p> +This page describes the API functions provided by the FFI library in +detail. It's recommended to read through the +<a href="ext_ffi.html">introduction</a> and the +<a href="ext_ffi_tutorial.html">FFI tutorial</a> first. +</p> + +<h2 id="glossary">Glossary</h2> +<ul> +<li><b>cdecl</b> — An abstract C type declaration (a Lua +string).</li> +<li><b>ctype</b> — A C type object. This is a special kind of +<b>cdata</b> returned by <tt>ffi.typeof()</tt>. It serves as a +<b>cdata</b> <a href="#ffi_new">constructor</a> when called.</li> +<li><b>cdata</b> — A C data object. It holds a value of the +corresponding <b>ctype</b>.</li> +<li><b>ct</b> — A C type specification which can be used for +most of the API functions. Either a <b>cdecl</b>, a <b>ctype</b> or a +<b>cdata</b> serving as a template type.</li> +<li><b>cb</b> — A callback object. This is a C data object +holding a special function pointer. Calling this function from +C code runs an associated Lua function.</li> +<li><b>VLA</b> — A variable-length array is declared with a +<tt>?</tt> instead of the number of elements, e.g. <tt>"int[?]"</tt>. +The number of elements (<tt>nelem</tt>) must be given when it's +<a href="#ffi_new">created</a>.</li> +<li><b>VLS</b> — A variable-length struct is a <tt>struct</tt> C +type where the last element is a <b>VLA</b>. The same rules for +declaration and creation apply.</li> +</ul> + +<h2 id="decl">Declaring and Accessing External Symbols</h2> +<p> +External symbols must be declared first and can then be accessed by +indexing a <a href="ext_ffi_semantics.html#clib">C library +namespace</a>, which automatically binds the symbol to a specific +library. +</p> + +<h3 id="ffi_cdef"><tt>ffi.cdef(def)</tt></h3> +<p> +Adds multiple C declarations for types or external symbols (named +variables or functions). <tt>def</tt> must be a Lua string. It's +recommended to use the syntactic sugar for string arguments as +follows: +</p> +<pre class="code"> +ffi.cdef[[ +<span style="color:#00a000;">typedef struct foo { int a, b; } foo_t; // Declare a struct and typedef. +int dofoo(foo_t *f, int n); /* Declare an external C function. */</span> +]] +</pre> +<p> +The contents of the string (the part in green above) must be a +sequence of +<a href="ext_ffi_semantics.html#clang">C declarations</a>, +separated by semicolons. The trailing semicolon for a single +declaration may be omitted. +</p> +<p> +Please note, that external symbols are only <em>declared</em>, but they +are <em>not bound</em> to any specific address, yet. Binding is +achieved with C library namespaces (see below). +</p> +<p style="color: #c00000;"> +C declarations are not passed through a C pre-processor, +yet. No pre-processor tokens are allowed, except for +<tt>#pragma pack</tt>. Replace <tt>#define</tt> in existing +C header files with <tt>enum</tt>, <tt>static const</tt> +or <tt>typedef</tt> and/or pass the files through an external +C pre-processor (once). Be careful not to include unneeded or +redundant declarations from unrelated header files. +</p> + +<h3 id="ffi_C"><tt>ffi.C</tt></h3> +<p> +This is the default C library namespace — note the +uppercase <tt>'C'</tt>. It binds to the default set of symbols or +libraries on the target system. These are more or less the same as a +C compiler would offer by default, without specifying extra link +libraries. +</p> +<p> +On POSIX systems, this binds to symbols in the default or global +namespace. This includes all exported symbols from the executable and +any libraries loaded into the global namespace. This includes at least +<tt>libc</tt>, <tt>libm</tt>, <tt>libdl</tt> (on Linux), +<tt>libgcc</tt> (if compiled with GCC), as well as any exported +symbols from the Lua/C API provided by LuaJIT itself. +</p> +<p> +On Windows systems, this binds to symbols exported from the +<tt>*.exe</tt>, the <tt>lua51.dll</tt> (i.e. the Lua/C API +provided by LuaJIT itself), the C runtime library LuaJIT was linked +with (<tt>msvcrt*.dll</tt>), <tt>kernel32.dll</tt>, +<tt>user32.dll</tt> and <tt>gdi32.dll</tt>. +</p> + +<h3 id="ffi_load"><tt>clib = ffi.load(name [,global])</tt></h3> +<p> +This loads the dynamic library given by <tt>name</tt> and returns +a new C library namespace which binds to its symbols. On POSIX +systems, if <tt>global</tt> is <tt>true</tt>, the library symbols are +loaded into the global namespace, too. +</p> +<p> +If <tt>name</tt> is a path, the library is loaded from this path. +Otherwise <tt>name</tt> is canonicalized in a system-dependent way and +searched in the default search path for dynamic libraries: +</p> +<p> +On POSIX systems, if the name contains no dot, the extension +<tt>.so</tt> is appended. Also, the <tt>lib</tt> prefix is prepended +if necessary. So <tt>ffi.load("z")</tt> looks for <tt>"libz.so"</tt> +in the default shared library search path. +</p> +<p> +On Windows systems, if the name contains no dot, the extension +<tt>.dll</tt> is appended. So <tt>ffi.load("ws2_32")</tt> looks for +<tt>"ws2_32.dll"</tt> in the default DLL search path. +</p> + +<h2 id="create">Creating cdata Objects</h2> +<p> +The following API functions create cdata objects (<tt>type()</tt> +returns <tt>"cdata"</tt>). All created cdata objects are +<a href="ext_ffi_semantics.html#gc">garbage collected</a>. +</p> + +<h3 id="ffi_new"><tt>cdata = ffi.new(ct [,nelem] [,init...])<br> +cdata = <em>ctype</em>([nelem,] [init...])</tt></h3> +<p> +Creates a cdata object for the given <tt>ct</tt>. VLA/VLS types +require the <tt>nelem</tt> argument. The second syntax uses a ctype as +a constructor and is otherwise fully equivalent. +</p> +<p> +The cdata object is initialized according to the +<a href="ext_ffi_semantics.html#init">rules for initializers</a>, +using the optional <tt>init</tt> arguments. Excess initializers cause +an error. +</p> +<p> +Performance notice: if you want to create many objects of one kind, +parse the cdecl only once and get its ctype with +<tt>ffi.typeof()</tt>. Then use the ctype as a constructor repeatedly. +</p> +<p style="font-size: 8pt;"> +Please note, that an anonymous <tt>struct</tt> declaration implicitly +creates a new and distinguished ctype every time you use it for +<tt>ffi.new()</tt>. This is probably <b>not</b> what you want, +especially if you create more than one cdata object. Different anonymous +<tt>structs</tt> are not considered assignment-compatible by the +C standard, even though they may have the same fields! Also, they +are considered different types by the JIT-compiler, which may cause an +excessive number of traces. It's strongly suggested to either declare +a named <tt>struct</tt> or <tt>typedef</tt> with <tt>ffi.cdef()</tt> +or to create a single ctype object for an anonymous <tt>struct</tt> +with <tt>ffi.typeof()</tt>. +</p> + +<h3 id="ffi_typeof"><tt>ctype = ffi.typeof(ct)</tt></h3> +<p> +Creates a ctype object for the given <tt>ct</tt>. +</p> +<p> +This function is especially useful to parse a cdecl only once and then +use the resulting ctype object as a <a href="#ffi_new">constructor</a>. +</p> + +<h3 id="ffi_cast"><tt>cdata = ffi.cast(ct, init)</tt></h3> +<p> +Creates a scalar cdata object for the given <tt>ct</tt>. The cdata +object is initialized with <tt>init</tt> using the "cast" variant of +the <a href="ext_ffi_semantics.html#convert">C type conversion +rules</a>. +</p> +<p> +This functions is mainly useful to override the pointer compatibility +checks or to convert pointers to addresses or vice versa. +</p> + +<h3 id="ffi_metatype"><tt>ctype = ffi.metatype(ct, metatable)</tt></h3> +<p> +Creates a ctype object for the given <tt>ct</tt> and associates it with +a metatable. Only <tt>struct</tt>/<tt>union</tt> types, complex numbers +and vectors are allowed. Other types may be wrapped in a +<tt>struct</tt>, if needed. +</p> +<p> +The association with a metatable is permanent and cannot be changed +afterwards. Neither the contents of the <tt>metatable</tt> nor the +contents of an <tt>__index</tt> table (if any) may be modified +afterwards. The associated metatable automatically applies to all uses +of this type, no matter how the objects are created or where they +originate from. Note that predefined operations on types have +precedence (e.g. declared field names cannot be overridden). +</p> +<p> +All standard Lua metamethods are implemented. These are called directly, +without shortcuts, and on any mix of types. For binary operations, the +left operand is checked first for a valid ctype metamethod. The +<tt>__gc</tt> metamethod only applies to <tt>struct</tt>/<tt>union</tt> +types and performs an implicit <a href="#ffi_gc"><tt>ffi.gc()</tt></a> +call during creation of an instance. +</p> + +<h3 id="ffi_gc"><tt>cdata = ffi.gc(cdata, finalizer)</tt></h3> +<p> +Associates a finalizer with a pointer or aggregate cdata object. The +cdata object is returned unchanged. +</p> +<p> +This function allows safe integration of unmanaged resources into the +automatic memory management of the LuaJIT garbage collector. Typical +usage: +</p> +<pre class="code"> +local p = ffi.gc(ffi.C.malloc(n), ffi.C.free) +... +p = nil -- Last reference to p is gone. +-- GC will eventually run finalizer: ffi.C.free(p) +</pre> +<p> +A cdata finalizer works like the <tt>__gc</tt> metamethod for userdata +objects: when the last reference to a cdata object is gone, the +associated finalizer is called with the cdata object as an argument. The +finalizer can be a Lua function or a cdata function or cdata function +pointer. An existing finalizer can be removed by setting a <tt>nil</tt> +finalizer, e.g. right before explicitly deleting a resource: +</p> +<pre class="code"> +ffi.C.free(ffi.gc(p, nil)) -- Manually free the memory. +</pre> + +<h2 id="info">C Type Information</h2> +<p> +The following API functions return information about C types. +They are most useful for inspecting cdata objects. +</p> + +<h3 id="ffi_sizeof"><tt>size = ffi.sizeof(ct [,nelem])</tt></h3> +<p> +Returns the size of <tt>ct</tt> in bytes. Returns <tt>nil</tt> if +the size is not known (e.g. for <tt>"void"</tt> or function types). +Requires <tt>nelem</tt> for VLA/VLS types, except for cdata objects. +</p> + +<h3 id="ffi_alignof"><tt>align = ffi.alignof(ct)</tt></h3> +<p> +Returns the minimum required alignment for <tt>ct</tt> in bytes. +</p> + +<h3 id="ffi_offsetof"><tt>ofs [,bpos,bsize] = ffi.offsetof(ct, field)</tt></h3> +<p> +Returns the offset (in bytes) of <tt>field</tt> relative to the start +of <tt>ct</tt>, which must be a <tt>struct</tt>. Additionally returns +the position and the field size (in bits) for bit fields. +</p> + +<h3 id="ffi_istype"><tt>status = ffi.istype(ct, obj)</tt></h3> +<p> +Returns <tt>true</tt> if <tt>obj</tt> has the C type given by +<tt>ct</tt>. Returns <tt>false</tt> otherwise. +</p> +<p> +C type qualifiers (<tt>const</tt> etc.) are ignored. Pointers are +checked with the standard pointer compatibility rules, but without any +special treatment for <tt>void *</tt>. If <tt>ct</tt> specifies a +<tt>struct</tt>/<tt>union</tt>, then a pointer to this type is accepted, +too. Otherwise the types must match exactly. +</p> +<p> +Note: this function accepts all kinds of Lua objects for the +<tt>obj</tt> argument, but always returns <tt>false</tt> for non-cdata +objects. +</p> + +<h2 id="util">Utility Functions</h2> + +<h3 id="ffi_errno"><tt>err = ffi.errno([newerr])</tt></h3> +<p> +Returns the error number set by the last C function call which +indicated an error condition. If the optional <tt>newerr</tt> argument +is present, the error number is set to the new value and the previous +value is returned. +</p> +<p> +This function offers a portable and OS-independent way to get and set the +error number. Note that only <em>some</em> C functions set the error +number. And it's only significant if the function actually indicated an +error condition (e.g. with a return value of <tt>-1</tt> or +<tt>NULL</tt>). Otherwise, it may or may not contain any previously set +value. +</p> +<p> +You're advised to call this function only when needed and as close as +possible after the return of the related C function. The +<tt>errno</tt> value is preserved across hooks, memory allocations, +invocations of the JIT compiler and other internal VM activity. The same +applies to the value returned by <tt>GetLastError()</tt> on Windows, but +you need to declare and call it yourself. +</p> + +<h3 id="ffi_string"><tt>str = ffi.string(ptr [,len])</tt></h3> +<p> +Creates an interned Lua string from the data pointed to by +<tt>ptr</tt>. +</p> +<p> +If the optional argument <tt>len</tt> is missing, <tt>ptr</tt> is +converted to a <tt>"char *"</tt> and the data is assumed to be +zero-terminated. The length of the string is computed with +<tt>strlen()</tt>. +</p> +<p> +Otherwise <tt>ptr</tt> is converted to a <tt>"void *"</tt> and +<tt>len</tt> gives the length of the data. The data may contain +embedded zeros and need not be byte-oriented (though this may cause +endianess issues). +</p> +<p> +This function is mainly useful to convert (temporary) +<tt>"const char *"</tt> pointers returned by +C functions to Lua strings and store them or pass them to other +functions expecting a Lua string. The Lua string is an (interned) copy +of the data and bears no relation to the original data area anymore. +Lua strings are 8 bit clean and may be used to hold arbitrary, +non-character data. +</p> +<p> +Performance notice: it's faster to pass the length of the string, if +it's known. E.g. when the length is returned by a C call like +<tt>sprintf()</tt>. +</p> + +<h3 id="ffi_copy"><tt>ffi.copy(dst, src, len)<br> +ffi.copy(dst, str)</tt></h3> +<p> +Copies the data pointed to by <tt>src</tt> to <tt>dst</tt>. +<tt>dst</tt> is converted to a <tt>"void *"</tt> and <tt>src</tt> +is converted to a <tt>"const void *"</tt>. +</p> +<p> +In the first syntax, <tt>len</tt> gives the number of bytes to copy. +Caveat: if <tt>src</tt> is a Lua string, then <tt>len</tt> must not +exceed <tt>#src+1</tt>. +</p> +<p> +In the second syntax, the source of the copy must be a Lua string. All +bytes of the string <em>plus a zero-terminator</em> are copied to +<tt>dst</tt> (i.e. <tt>#src+1</tt> bytes). +</p> +<p> +Performance notice: <tt>ffi.copy()</tt> may be used as a faster +(inlinable) replacement for the C library functions +<tt>memcpy()</tt>, <tt>strcpy()</tt> and <tt>strncpy()</tt>. +</p> + +<h3 id="ffi_fill"><tt>ffi.fill(dst, len [,c])</tt></h3> +<p> +Fills the data pointed to by <tt>dst</tt> with <tt>len</tt> constant +bytes, given by <tt>c</tt>. If <tt>c</tt> is omitted, the data is +zero-filled. +</p> +<p> +Performance notice: <tt>ffi.fill()</tt> may be used as a faster +(inlinable) replacement for the C library function +<tt>memset(dst, c, len)</tt>. Please note the different +order of arguments! +</p> + +<h2 id="target">Target-specific Information</h2> + +<h3 id="ffi_abi"><tt>status = ffi.abi(param)</tt></h3> +<p> +Returns <tt>true</tt> if <tt>param</tt> (a Lua string) applies for the +target ABI (Application Binary Interface). Returns <tt>false</tt> +otherwise. The following parameters are currently defined: +</p> +<table class="abitable"> +<tr class="abihead"> +<td class="abiparam">Parameter</td> +<td class="abidesc">Description</td> +</tr> +<tr class="odd separate"> +<td class="abiparam">32bit</td><td class="abidesc">32 bit architecture</td></tr> +<tr class="even"> +<td class="abiparam">64bit</td><td class="abidesc">64 bit architecture</td></tr> +<tr class="odd separate"> +<td class="abiparam">le</td><td class="abidesc">Little-endian architecture</td></tr> +<tr class="even"> +<td class="abiparam">be</td><td class="abidesc">Big-endian architecture</td></tr> +<tr class="odd separate"> +<td class="abiparam">fpu</td><td class="abidesc">Target has a hardware FPU</td></tr> +<tr class="even"> +<td class="abiparam">softfp</td><td class="abidesc">softfp calling conventions</td></tr> +<tr class="odd"> +<td class="abiparam">hardfp</td><td class="abidesc">hardfp calling conventions</td></tr> +<tr class="even separate"> +<td class="abiparam">eabi</td><td class="abidesc">EABI variant of the standard ABI</td></tr> +<tr class="odd"> +<td class="abiparam">win</td><td class="abidesc">Windows variant of the standard ABI</td></tr> +<tr class="even"> +<td class="abiparam">uwp</td><td class="abidesc">Universal Windows Platform</td></tr> +<tr class="odd"> +<td class="abiparam">gc64</td><td class="abidesc">64 bit GC references</td></tr> +</table> + +<h3 id="ffi_os"><tt>ffi.os</tt></h3> +<p> +Contains the target OS name. Same contents as +<a href="ext_jit.html#jit_os"><tt>jit.os</tt></a>. +</p> + +<h3 id="ffi_arch"><tt>ffi.arch</tt></h3> +<p> +Contains the target architecture name. Same contents as +<a href="ext_jit.html#jit_arch"><tt>jit.arch</tt></a>. +</p> + +<h2 id="callback">Methods for Callbacks</h2> +<p> +The C types for <a href="ext_ffi_semantics.html#callback">callbacks</a> +have some extra methods: +</p> + +<h3 id="callback_free"><tt>cb:free()</tt></h3> +<p> +Free the resources associated with a callback. The associated Lua +function is unanchored and may be garbage collected. The callback +function pointer is no longer valid and must not be called again +(it may be reused by a subsequently created callback). +</p> + +<h3 id="callback_set"><tt>cb:set(func)</tt></h3> +<p> +Associate a new Lua function with a callback. The C type of the +callback and the callback function pointer are unchanged. +</p> +<p> +This method is useful to dynamically switch the receiver of callbacks +without creating a new callback each time and registering it again (e.g. +with a GUI library). +</p> + +<h2 id="extended">Extended Standard Library Functions</h2> +<p> +The following standard library functions have been extended to work +with cdata objects: +</p> + +<h3 id="tonumber"><tt>n = tonumber(cdata)</tt></h3> +<p> +Converts a number cdata object to a <tt>double</tt> and returns it as +a Lua number. This is particularly useful for boxed 64 bit +integer values. Caveat: this conversion may incur a precision loss. +</p> + +<h3 id="tostring"><tt>s = tostring(cdata)</tt></h3> +<p> +Returns a string representation of the value of 64 bit integers +(<tt><b>"</b>nnn<b>LL"</b></tt> or <tt><b>"</b>nnn<b>ULL"</b></tt>) or +complex numbers (<tt><b>"</b>re±im<b>i"</b></tt>). Otherwise +returns a string representation of the C type of a ctype object +(<tt><b>"ctype<</b>type<b>>"</b></tt>) or a cdata object +(<tt><b>"cdata<</b>type<b>>: </b>address"</tt>), unless you +override it with a <tt>__tostring</tt> metamethod (see +<a href="#ffi_metatype"><tt>ffi.metatype()</tt></a>). +</p> + +<h3 id="pairs"><tt>iter, obj, start = pairs(cdata)<br> +iter, obj, start = ipairs(cdata)<br></tt></h3> +<p> +Calls the <tt>__pairs</tt> or <tt>__ipairs</tt> metamethod of the +corresponding ctype. +</p> + +<h2 id="literals">Extensions to the Lua Parser</h2> +<p> +The parser for Lua source code treats numeric literals with the +suffixes <tt>LL</tt> or <tt>ULL</tt> as signed or unsigned 64 bit +integers. Case doesn't matter, but uppercase is recommended for +readability. It handles decimal (<tt>42LL</tt>), hexadecimal +(<tt>0x2aLL</tt>) and binary (<tt>0b101010LL</tt>) literals. +</p> +<p> +The imaginary part of complex numbers can be specified by suffixing +number literals with <tt>i</tt> or <tt>I</tt>, e.g. <tt>12.5i</tt>. +Caveat: you'll need to use <tt>1i</tt> to get an imaginary part with +the value one, since <tt>i</tt> itself still refers to a variable +named <tt>i</tt>. +</p> +<br class="flush"> +</div> +<div id="foot"> +<hr class="hide"> +Copyright © 2005-2022 +<span class="noprint"> +· +<a href="contact.html">Contact</a> +</span> +</div> +</body> +</html> |