What’s New¶
v1.9¶
- Structs with variable-sized arrays as their last field: now we track
the length of the array after
ffi.new()
is called, just like we always tracked the length offfi.new("int[]", 42)
. This lets us detect out-of-range accesses to array items. This also lets us display a betterrepr()
, and have the total size returned byffi.sizeof()
andffi.buffer()
. Previously both functions would return a result based on the size of the declared structure type, with an assumed empty array. (Thanks andrew for starting this refactoring.) - Add support in
cdef()/set_source()
for unspecified-length arrays in typedefs:typedef int foo_t[...];
. It was already supported for global variables or structure fields. - I turned in v1.8 a warning from
cffi/model.py
into an error:'enum xxx' has no values explicitly defined: refusing to guess which integer type it is meant to be (unsigned/signed, int/long)
. Now I’m turning it back to a warning again; it seems that guessing that the enum has sizeint
is a 99%-safe bet. (But not 100%, so it stays as a warning.) - Fix leaks in the code handling
FILE *
arguments. In CPython 3 there is a remaining issue that is hard to fix: if you pass a Python file object to aFILE *
argument, thenos.dup()
is used and the new file descriptor is only closed when the GC reclaims the Python file object—and not at the earlier time when you callclose()
, which only closes the original file descriptor. If this is an issue, you should avoid this automatic convertion of Python file objects: instead, explicitly manipulate file descriptors and callfdopen()
from C (...via cffi).
v1.8.3¶
- When passing a
void *
argument to a function with a different pointer type, or vice-versa, the cast occurs automatically, like in C. The same occurs for initialization withffi.new()
and a few other places. However, I thought thatchar *
had the same property—but I was mistaken. In C you get the usual warning if you try to give achar *
to achar **
argument, for example. Sorry about the confusion. This has been fixed in CFFI by giving for now a warning, too. It will turn into an error in a future version.
v1.8.2¶
- Issue #283: fixed
ffi.new()
on structures/unions with nested anonymous structures/unions, when there is at least one union in the mix. When initialized with a list or a dict, it should now behave more closely like the{ }
syntax does in GCC.
v1.8.1¶
- CPython 3.x: experimental: the generated C extension modules now use
the “limited API”, which means that, as a compiled .so/.dll, it should
work directly on any version of CPython >= 3.2. The name produced by
distutils is still version-specific. To get the version-independent
name, you can rename it manually to
NAME.abi3.so
, or use the very recent setuptools 26. - Added
ffi.compile(debug=...)
, similar topython setup.py build --debug
but defaulting to True if we are running a debugging version of Python itself.
v1.8¶
- Removed the restriction that
ffi.from_buffer()
cannot be used on byte strings. Now you can get achar *
out of a byte string, which is valid as long as the string object is kept alive. (But don’t use it to modify the string object! If you need this, usebytearray
or other official techniques.) - PyPy 5.4 can now pass a byte string directly to a
char *
argument (in older versions, a copy would be made). This used to be a CPython-only optimization.
v1.7¶
ffi.gc(p, None)
removes the destructor on an object previously created by another call toffi.gc()
bool(ffi.cast("primitive type", x))
now returns False if the value is zero (including-0.0
), and True otherwise. Previously this would only return False for cdata objects of a pointer type when the pointer is NULL.- bytearrays:
ffi.from_buffer(bytearray-object)
is now supported. (The reason it was not supported was that it was hard to do in PyPy, but it works since PyPy 5.3.) To call a C function with achar *
argument from a buffer object—now including bytearrays—you writelib.foo(ffi.from_buffer(x))
. Additionally, this is now supported:p[0:length] = bytearray-object
. The problem with this was that a iterating over bytearrays gives numbers instead of characters. (Now it is implemented with just a memcpy, of course, not actually iterating over the characters.) - C++: compiling the generated C code with C++ was supposed to work,
but failed if you make use the
bool
type (because that is rendered as the C_Bool
type, which doesn’t exist in C++). help(lib)
andhelp(lib.myfunc)
now give useful information, as well asdir(p)
wherep
is a struct or pointer-to-struct.
v1.6¶
- ffi.list_types()
- ffi.unpack()
- extern “Python+C”
- in API mode,
lib.foo.__doc__
contains the C signature now. On CPython you can sayhelp(lib.foo)
, but for some reasonhelp(lib)
(orhelp(lib.foo)
on PyPy) is still useless; I haven’t yet figured out the hacks needed to convincepydoc
to show more. (You can usedir(lib)
but it is not most helpful.) - Yet another attempt at robustness of
ffi.def_extern()
against CPython’s interpreter shutdown logic.
v1.5.2¶
- Fix 1.5.1 for Python 2.6.
v1.5.1¶
- A few installation-time tweaks (thanks Stefano!)
- Issue #245: Win32:
__stdcall
was never generated forextern "Python"
functions - Issue #246: trying to be more robust against CPython’s fragile interpreter shutdown logic
v1.5.0¶
- Support for using CFFI for embedding.
v1.4.2¶
Nothing changed from v1.4.1.
v1.4.1¶
- Fix the compilation failure of cffi on CPython 3.5.0. (3.5.1 works; some detail changed that makes some underscore-starting macros disappear from view of extension modules, and I worked around it, thinking it changed in all 3.5 versions—but no: it was only in 3.5.1.)
v1.4.0¶
- A better way to do callbacks has been added (faster and more
portable, and usually cleaner). It is a mechanism for the
out-of-line API mode that replaces the dynamic creation of callback
objects (i.e. C functions that invoke Python) with the static
declaration in
cdef()
of which callbacks are needed. This is more C-like, in that you have to structure your code around the idea that you get a fixed number of function pointers, instead of creating them on-the-fly. ffi.compile()
now takes an optionalverbose
argument. WhenTrue
, distutils prints the calls to the compiler.ffi.compile()
used to fail if givensources
with a path that includes".."
. Fixed.ffi.init_once()
added. See docs.dir(lib)
now works on libs returned byffi.dlopen()
too.- Cleaned up and modernized the content of the
demo
subdirectory in the sources (thanks matti!). ffi.new_handle()
is now guaranteed to return uniquevoid *
values, even if called twice on the same object. Previously, in that case, CPython would return twocdata
objects with the samevoid *
value. This change is useful to add and remove handles from a global dict (or set) without worrying about duplicates. It already used to work like that on PyPy. This change can break code that used to work on CPython by relying on the object to be kept alive by other means than keeping the result of ffi.new_handle() alive. (The corresponding warning in the docs offfi.new_handle()
has been here since v0.8!)
v1.3.1¶
- The optional typedefs (
bool
,FILE
and all Windows types) were not always available from out-of-line FFI objects. - Opaque enums are phased out from the cdefs: they now give a warning,
instead of (possibly wrongly) being assumed equal to
unsigned int
. Please report if you get a reasonable use case for them. - Some parsing details, notably
volatile
is passed along likeconst
andrestrict
. Also, older versions of pycparser mis-parse some pointer-to-pointer types likechar * const *
: the “const” ends up at the wrong place. Added a workaround.
v1.3.0¶
- Added ffi.memmove().
- Pull request #64: out-of-line API mode: we can now declare
floating-point types with
typedef float... foo_t;
. This only works iffoo_t
is a float or a double, notlong double
. - Issue #217: fix possible unaligned pointer manipulation, which crashes on some architectures (64-bit, non-x86).
- Issues #64 and #126: when using
set_source()
orverify()
, theconst
andrestrict
keywords are copied from the cdef to the generated C code; this fixes warnings by the C compiler. It also fixes corner cases liketypedef const int T; T a;
which would previously not considera
as a constant. (The cdata objects themselves are neverconst
.) - Win32: support for
__stdcall
. For callbacks and function pointers; regular C functions still don’t need to have their calling convention declared. - Windows: CPython 2.7 distutils doesn’t work with Microsoft’s official
Visual Studio for Python, and I’m told this is not a bug. For
ffi.compile(), we removed a workaround that was inside cffi but
which had unwanted side-effects. Try saying
import setuptools
first, which patches distutils...
v1.2.1¶
Nothing changed from v1.2.0.
v1.2.0¶
- Out-of-line mode:
int a[][...];
can be used to declare a structure field or global variable which is, simultaneously, of total length unknown to the C compiler (thea[]
part) and each element is itself an array of N integers, where the value of N is known to the C compiler (theint
and[...]
parts around it). Similarly,int a[5][...];
is supported (but probably less useful: remember that in C it meansint (a[5])[...];
). - PyPy: the
lib.some_function
objects were missing the attributes__name__
,__module__
and__doc__
that are expected e.g. by some decorators-management functions fromfunctools
. - Out-of-line API mode: you can now do
from _example.lib import x
to import the namex
from_example.lib
, even though thelib
object is not a standard module object. (Also works infrom _example.lib import *
, but this is even more of a hack and will fail iflib
happens to declare a name called__all__
. Note that*
excludes the global variables; only the functions and constants make sense to import like this.) lib.__dict__
works again and gives you a copy of the dict—assuming thatlib
has got no symbol called precisely__dict__
. (In general, it is safer to usedir(lib)
.)- Out-of-line API mode: global variables are now fetched on demand at
every access. It fixes issue #212 (Windows DLL variables), and also
allows variables that are defined as dynamic macros (like
errno
) or__thread
-local variables. (This change might also tighten the C compiler’s check on the variables’ type.) - Issue #209: dereferencing NULL pointers now raises RuntimeError instead of segfaulting. Meant as a debugging aid. The check is only for NULL: if you dereference random or dead pointers you might still get segfaults.
- Issue #152: callbacks: added an argument
ffi.callback(..., onerror=...)
. If the main callback function raises an exception andonerror
is provided, thenonerror(exception, exc_value, traceback)
is called. This is similar to writing atry: except:
in the main callback function, but in some cases (e.g. a signal) an exception can occur at the very start of the callback function—before it had time to enter thetry: except:
block. - Issue #115: added
ffi.new_allocator()
, which officializes support for alternative allocators.
v1.1.2¶
ffi.gc()
: fixed a race condition in multithreaded programs introduced in 1.1.1
v1.1.1¶
- Out-of-line mode:
ffi.string()
,ffi.buffer()
andffi.getwinerror()
didn’t accept their arguments as keyword arguments, unlike their in-line mode equivalent. (It worked in PyPy.) - Out-of-line ABI mode: documented a restriction of
ffi.dlopen()
when compared to the in-line mode. ffi.gc()
: when called several times with equal pointers, it was accidentally registering only the last destructor, or even none at all depending on details. (It was correctly registering all of them only in PyPy, and only with the out-of-line FFIs.)
v1.1.0¶
- Out-of-line API mode: we can now declare integer types with
typedef int... foo_t;
. The exact size and signedness offoo_t
is figured out by the compiler. - Out-of-line API mode: we can now declare multidimensional arrays
(as fields or as globals) with
int n[...][...]
. Before, only the outermost dimension would support the...
syntax. - Out-of-line ABI mode: we now support any constant declaration,
instead of only integers whose value is given in the cdef. Such “new”
constants, i.e. either non-integers or without a value given in the
cdef, must correspond to actual symbols in the lib. At runtime they
are looked up the first time we access them. This is useful if the
library defines
extern const sometype somename;
. ffi.addressof(lib, "func_name")
now returns a regular cdata object of type “pointer to function”. You can use it on any function from a library in API mode (in ABI mode, all functions are already regular cdata objects). To support this, you need to recompile your cffi modules.- Issue #198: in API mode, if you declare constants of a
struct
type, what you saw from lib.CONSTANT was corrupted. - Issue #196:
ffi.set_source("package._ffi", None)
would incorrectly generate the Python source topackage._ffi.py
instead ofpackage/_ffi.py
. Also fixed: in some cases, if the C file was inbuild/foo.c
, the .o file would be put inbuild/build/foo.o
.
v1.0.3¶
- Same as 1.0.2, apart from doc and test fixes on some platforms.
v1.0.2¶
- Variadic C functions (ending in a ”...” argument) were not supported in the out-of-line ABI mode. This was a bug—there was even a (non-working) example doing exactly that!
v1.0.1¶
ffi.set_source()
crashed if passed asources=[..]
argument. Fixed by chrippa on pull request #60.- Issue #193: if we use a struct between the first cdef() where it is declared and another cdef() where its fields are defined, then this definition was ignored.
- Enums were buggy if you used too many ”...” in their definition.
v1.0.0¶
- The main news item is out-of-line module generation:
- for ABI level, with
ffi.dlopen()
- for API level, which used to be with
ffi.verify()
, now deprecated
- for ABI level, with
- (this page will list what is new from all versions from 1.0.0 forward.)