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cffi (package)

This module has no docstring.

Classes

CDefError

with_traceback(...)

  Exception.with_traceback(tb) --
      set self.__traceback__ to tb and return self.
args = <attribute 'args' of 'BaseException' objects>

FFI


    The main top-level class that you instantiate once, or once per module.

    Example usage:

        ffi = FFI()
        ffi.cdef("""
            int printf(const char *, ...);
        """)

        C = ffi.dlopen(None)   # standard library
        -or-
        C = ffi.verify()  # use a C compiler: verify the decl above is right

        C.printf("hello, %s!\n", ffi.new("char[]", "world"))
    
addressof(self, cdata, *fields_or_indexes)

  Return the address of a <cdata 'struct-or-union'>.
          If 'fields_or_indexes' are given, returns the address of that
          field or array item in the structure or array, recursively in
          case of nested structures.
        
alignof(self, cdecl)

  Return the natural alignment size in bytes of the C type
          given as a string.
        
callback(self, cdecl, python_callable=None, error=None, onerror=None)

  Return a callback object or a decorator making such a
          callback object.  'cdecl' must name a C function pointer type.
          The callback invokes the specified 'python_callable' (which may
          be provided either directly or via a decorator).  Important: the
          callback object must be manually kept alive for as long as the
          callback may be invoked from the C level.
        
cast(self, cdecl, source)

  Similar to a C cast: returns an instance of the named C
          type initialized with the given 'source'.  The source is
          casted between integers or pointers of any type.
        
cdef(self, csource, override=False, packed=False, pack=None)

  Parse the given C source.  This registers all declared functions,
          types, and global variables.  The functions and global variables can
          then be accessed via either 'ffi.dlopen()' or 'ffi.verify()'.
          The types can be used in 'ffi.new()' and other functions.
          If 'packed' is specified as True, all structs declared inside this
          cdef are packed, i.e. laid out without any field alignment at all.
          Alternatively, 'pack' can be a small integer, and requests for
          alignment greater than that are ignored (pack=1 is equivalent to
          packed=True).
        
compile(self, tmpdir='.', verbose=0, target=None, debug=None)

  The 'target' argument gives the final file name of the
          compiled DLL.  Use '*' to force distutils' choice, suitable for
          regular CPython C API modules.  Use a file name ending in '.*'
          to ask for the system's default extension for dynamic libraries
          (.so/.dll/.dylib).

          The default is '*' when building a non-embedded C API extension,
          and (module_name + '.*') when building an embedded library.
        
def_extern(self, *args, **kwds)
distutils_extension(self, tmpdir='build', verbose=True)
dlclose(self, lib)

  Close a library obtained with ffi.dlopen().  After this call,
          access to functions or variables from the library will fail
          (possibly with a segmentation fault).
        
dlopen(self, name, flags=0)

  Load and return a dynamic library identified by 'name'.
          The standard C library can be loaded by passing None.
          Note that functions and types declared by 'ffi.cdef()' are not
          linked to a particular library, just like C headers; in the
          library we only look for the actual (untyped) symbols.
        
embedding_api(self, csource, packed=False, pack=None)
embedding_init_code(self, pysource)
emit_c_code(self, filename)
emit_python_code(self, filename)
from_buffer(self, cdecl, python_buffer=<object object at 0x7f75e3c96870>, require_writable=False)

  Return a cdata of the given type pointing to the data of the
          given Python object, which must support the buffer interface.
          Note that this is not meant to be used on the built-in types
          str or unicode (you can build 'char[]' arrays explicitly)
          but only on objects containing large quantities of raw data
          in some other format, like 'array.array' or numpy arrays.

          The first argument is optional and default to 'char[]'.
        
from_handle(self, x)
gc(self, cdata, destructor, size=0)

  Return a new cdata object that points to the same
          data.  Later, when this new cdata object is garbage-collected,
          'destructor(old_cdata_object)' will be called.

          The optional 'size' gives an estimate of the size, used to
          trigger the garbage collection more eagerly.  So far only used
          on PyPy.  It tells the GC that the returned object keeps alive
          roughly 'size' bytes of external memory.
        
getctype(self, cdecl, replace_with='')

  Return a string giving the C type 'cdecl', which may be itself
          a string or a <ctype> object.  If 'replace_with' is given, it gives
          extra text to append (or insert for more complicated C types), like
          a variable name, or '*' to get actually the C type 'pointer-to-cdecl'.
        
getwinerror(self, code=-1)
include(self, ffi_to_include)

  Includes the typedefs, structs, unions and enums defined
          in another FFI instance.  Usage is similar to a #include in C,
          where a part of the program might include types defined in
          another part for its own usage.  Note that the include()
          method has no effect on functions, constants and global
          variables, which must anyway be accessed directly from the
          lib object returned by the original FFI instance.
        
init_once(self, func, tag)
list_types(self)

  Returns the user type names known to this FFI instance.
          This returns a tuple containing three lists of names:
          (typedef_names, names_of_structs, names_of_unions)
        
memmove(self, dest, src, n)

  ffi.memmove(dest, src, n) copies n bytes of memory from src to dest.

          Like the C function memmove(), the memory areas may overlap;
          apart from that it behaves like the C function memcpy().

          'src' can be any cdata ptr or array, or any Python buffer object.
          'dest' can be any cdata ptr or array, or a writable Python buffer
          object.  The size to copy, 'n', is always measured in bytes.

          Unlike other methods, this one supports all Python buffer including
          byte strings and bytearrays---but it still does not support
          non-contiguous buffers.
        
new(self, cdecl, init=None)

  Allocate an instance according to the specified C type and
          return a pointer to it.  The specified C type must be either a
          pointer or an array: ``new('X *')`` allocates an X and returns
          a pointer to it, whereas ``new('X[n]')`` allocates an array of
          n X'es and returns an array referencing it (which works
          mostly like a pointer, like in C).  You can also use
          ``new('X[]', n)`` to allocate an array of a non-constant
          length n.

          The memory is initialized following the rules of declaring a
          global variable in C: by default it is zero-initialized, but
          an explicit initializer can be given which can be used to
          fill all or part of the memory.

          When the returned <cdata> object goes out of scope, the memory
          is freed.  In other words the returned <cdata> object has
          ownership of the value of type 'cdecl' that it points to.  This
          means that the raw data can be used as long as this object is
          kept alive, but must not be used for a longer time.  Be careful
          about that when copying the pointer to the memory somewhere
          else, e.g. into another structure.
        
new_allocator(self, alloc=None, free=None, should_clear_after_alloc=True)

  Return a new allocator, i.e. a function that behaves like ffi.new()
          but uses the provided low-level 'alloc' and 'free' functions.

          'alloc' is called with the size as argument.  If it returns NULL, a
          MemoryError is raised.  'free' is called with the result of 'alloc'
          as argument.  Both can be either Python function or directly C
          functions.  If 'free' is None, then no free function is called.
          If both 'alloc' and 'free' are None, the default is used.

          If 'should_clear_after_alloc' is set to False, then the memory
          returned by 'alloc' is assumed to be already cleared (or you are
          fine with garbage); otherwise CFFI will clear it.
        
new_handle(self, x)
offsetof(self, cdecl, *fields_or_indexes)

  Return the offset of the named field inside the given
          structure or array, which must be given as a C type name.
          You can give several field names in case of nested structures.
          You can also give numeric values which correspond to array
          items, in case of an array type.
        
release(self, x)
set_source(self, module_name, source, source_extension='.c', **kwds)
set_source_pkgconfig(self, module_name, pkgconfig_libs, source, source_extension='.c', **kwds)
set_unicode(self, enabled_flag)

  Windows: if 'enabled_flag' is True, enable the UNICODE and
          _UNICODE defines in C, and declare the types like TCHAR and LPTCSTR
          to be (pointers to) wchar_t.  If 'enabled_flag' is False,
          declare these types to be (pointers to) plain 8-bit characters.
          This is mostly for backward compatibility; you usually want True.
        
sizeof(self, cdecl)

  Return the size in bytes of the argument.  It can be a
          string naming a C type, or a 'cdata' instance.
        
string(self, cdata, maxlen=-1)

  Return a Python string (or unicode string) from the 'cdata'.
          If 'cdata' is a pointer or array of characters or bytes, returns
          the null-terminated string.  The returned string extends until
          the first null character, or at most 'maxlen' characters.  If
          'cdata' is an array then 'maxlen' defaults to its length.

          If 'cdata' is a pointer or array of wchar_t, returns a unicode
          string following the same rules.

          If 'cdata' is a single character or byte or a wchar_t, returns
          it as a string or unicode string.

          If 'cdata' is an enum, returns the value of the enumerator as a
          string, or 'NUMBER' if the value is out of range.
        
typeof(self, cdecl)

  Parse the C type given as a string and return the
          corresponding <ctype> object.
          It can also be used on 'cdata' instance to get its C type.
        
unpack(self, cdata, length)

  Unpack an array of C data of the given length,
          returning a Python string/unicode/list.

          If 'cdata' is a pointer to 'char', returns a byte string.
          It does not stop at the first null.  This is equivalent to:
          ffi.buffer(cdata, length)[:]

          If 'cdata' is a pointer to 'wchar_t', returns a unicode string.
          'length' is measured in wchar_t's; it is not the size in bytes.

          If 'cdata' is a pointer to anything else, returns a list of
          'length' items.  This is a faster equivalent to:
          [cdata[i] for i in range(length)]
        
verify(self, source='', tmpdir=None, **kwargs)

  Verify that the current ffi signatures compile on this
          machine, and return a dynamic library object.  The dynamic
          library can be used to call functions and access global
          variables declared in this 'ffi'.  The library is compiled
          by the C compiler: it gives you C-level API compatibility
          (including calling macros).  This is unlike 'ffi.dlopen()',
          which requires binary compatibility in the signatures.
        
errno = <property object at 0x7f75e070bd30>
  the value of 'errno' from/to the C calls

FFIError

with_traceback(...)

  Exception.with_traceback(tb) --
      set self.__traceback__ to tb and return self.
args = <attribute 'args' of 'BaseException' objects>

PkgConfigError

 An error raised for missing modules in pkg-config
    
with_traceback(...)

  Exception.with_traceback(tb) --
      set self.__traceback__ to tb and return self.
args = <attribute 'args' of 'BaseException' objects>

VerificationError

 An error raised when verification fails
    
with_traceback(...)

  Exception.with_traceback(tb) --
      set self.__traceback__ to tb and return self.
args = <attribute 'args' of 'BaseException' objects>

VerificationMissing

 An error raised when incomplete structures are passed into
    cdef, but no verification has been done
    
with_traceback(...)

  Exception.with_traceback(tb) --
      set self.__traceback__ to tb and return self.
args = <attribute 'args' of 'BaseException' objects>

Modules

api

error

lock

model