This module has no docstring.
with_traceback(...)
Exception.with_traceback(tb) --
set self.__traceback__ to tb and return self.
args = <attribute 'args' of 'BaseException' objects>
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 0x7ff35e9d9290>, 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 0x7ff35e99e090> the value of 'errno' from/to the C calls
str(object='') -> str str(bytes_or_buffer[, encoding[, errors]]) -> str Create a new string object from the given object. If encoding or errors is specified, then the object must expose a data buffer that will be decoded using the given encoding and error handler. Otherwise, returns the result of object.__str__() (if defined) or repr(object). encoding defaults to sys.getdefaultencoding(). errors defaults to 'strict'.
capitalize(self, /) Return a capitalized version of the string. More specifically, make the first character have upper case and the rest lower case.
casefold(self, /) Return a version of the string suitable for caseless comparisons.
center(self, width, fillchar=' ', /) Return a centered string of length width. Padding is done using the specified fill character (default is a space).
count(...) S.count(sub[, start[, end]]) -> int Return the number of non-overlapping occurrences of substring sub in string S[start:end]. Optional arguments start and end are interpreted as in slice notation.
encode(self, /, encoding='utf-8', errors='strict')
Encode the string using the codec registered for encoding.
encoding
The encoding in which to encode the string.
errors
The error handling scheme to use for encoding errors.
The default is 'strict' meaning that encoding errors raise a
UnicodeEncodeError. Other possible values are 'ignore', 'replace' and
'xmlcharrefreplace' as well as any other name registered with
codecs.register_error that can handle UnicodeEncodeErrors.
endswith(...) S.endswith(suffix[, start[, end]]) -> bool Return True if S ends with the specified suffix, False otherwise. With optional start, test S beginning at that position. With optional end, stop comparing S at that position. suffix can also be a tuple of strings to try.
expandtabs(self, /, tabsize=8) Return a copy where all tab characters are expanded using spaces. If tabsize is not given, a tab size of 8 characters is assumed.
find(...) S.find(sub[, start[, end]]) -> int Return the lowest index in S where substring sub is found, such that sub is contained within S[start:end]. Optional arguments start and end are interpreted as in slice notation. Return -1 on failure.
format(...)
S.format(*args, **kwargs) -> str
Return a formatted version of S, using substitutions from args and kwargs.
The substitutions are identified by braces ('{' and '}').
format_map(...)
S.format_map(mapping) -> str
Return a formatted version of S, using substitutions from mapping.
The substitutions are identified by braces ('{' and '}').
index(...) S.index(sub[, start[, end]]) -> int Return the lowest index in S where substring sub is found, such that sub is contained within S[start:end]. Optional arguments start and end are interpreted as in slice notation. Raises ValueError when the substring is not found.
isalnum(self, /) Return True if the string is an alpha-numeric string, False otherwise. A string is alpha-numeric if all characters in the string are alpha-numeric and there is at least one character in the string.
isalpha(self, /) Return True if the string is an alphabetic string, False otherwise. A string is alphabetic if all characters in the string are alphabetic and there is at least one character in the string.
isascii(self, /) Return True if all characters in the string are ASCII, False otherwise. ASCII characters have code points in the range U+0000-U+007F. Empty string is ASCII too.
isdecimal(self, /) Return True if the string is a decimal string, False otherwise. A string is a decimal string if all characters in the string are decimal and there is at least one character in the string.
isdigit(self, /) Return True if the string is a digit string, False otherwise. A string is a digit string if all characters in the string are digits and there is at least one character in the string.
isidentifier(self, /) Return True if the string is a valid Python identifier, False otherwise. Call keyword.iskeyword(s) to test whether string s is a reserved identifier, such as "def" or "class".
islower(self, /) Return True if the string is a lowercase string, False otherwise. A string is lowercase if all cased characters in the string are lowercase and there is at least one cased character in the string.
isnumeric(self, /) Return True if the string is a numeric string, False otherwise. A string is numeric if all characters in the string are numeric and there is at least one character in the string.
isprintable(self, /) Return True if the string is printable, False otherwise. A string is printable if all of its characters are considered printable in repr() or if it is empty.
isspace(self, /) Return True if the string is a whitespace string, False otherwise. A string is whitespace if all characters in the string are whitespace and there is at least one character in the string.
istitle(self, /) Return True if the string is a title-cased string, False otherwise. In a title-cased string, upper- and title-case characters may only follow uncased characters and lowercase characters only cased ones.
isupper(self, /) Return True if the string is an uppercase string, False otherwise. A string is uppercase if all cased characters in the string are uppercase and there is at least one cased character in the string.
join(self, iterable, /) Concatenate any number of strings. The string whose method is called is inserted in between each given string. The result is returned as a new string. Example: '.'.join(['ab', 'pq', 'rs']) -> 'ab.pq.rs'
ljust(self, width, fillchar=' ', /) Return a left-justified string of length width. Padding is done using the specified fill character (default is a space).
lower(self, /) Return a copy of the string converted to lowercase.
lstrip(self, chars=None, /) Return a copy of the string with leading whitespace removed. If chars is given and not None, remove characters in chars instead.
maketrans(...) Return a translation table usable for str.translate(). If there is only one argument, it must be a dictionary mapping Unicode ordinals (integers) or characters to Unicode ordinals, strings or None. Character keys will be then converted to ordinals. If there are two arguments, they must be strings of equal length, and in the resulting dictionary, each character in x will be mapped to the character at the same position in y. If there is a third argument, it must be a string, whose characters will be mapped to None in the result.
partition(self, sep, /) Partition the string into three parts using the given separator. This will search for the separator in the string. If the separator is found, returns a 3-tuple containing the part before the separator, the separator itself, and the part after it. If the separator is not found, returns a 3-tuple containing the original string and two empty strings.
removeprefix(self, prefix, /) Return a str with the given prefix string removed if present. If the string starts with the prefix string, return string[len(prefix):]. Otherwise, return a copy of the original string.
removesuffix(self, suffix, /) Return a str with the given suffix string removed if present. If the string ends with the suffix string and that suffix is not empty, return string[:-len(suffix)]. Otherwise, return a copy of the original string.
replace(self, old, new, count=-1, /)
Return a copy with all occurrences of substring old replaced by new.
count
Maximum number of occurrences to replace.
-1 (the default value) means replace all occurrences.
If the optional argument count is given, only the first count occurrences are
replaced.
rfind(...) S.rfind(sub[, start[, end]]) -> int Return the highest index in S where substring sub is found, such that sub is contained within S[start:end]. Optional arguments start and end are interpreted as in slice notation. Return -1 on failure.
rindex(...) S.rindex(sub[, start[, end]]) -> int Return the highest index in S where substring sub is found, such that sub is contained within S[start:end]. Optional arguments start and end are interpreted as in slice notation. Raises ValueError when the substring is not found.
rjust(self, width, fillchar=' ', /) Return a right-justified string of length width. Padding is done using the specified fill character (default is a space).
rpartition(self, sep, /) Partition the string into three parts using the given separator. This will search for the separator in the string, starting at the end. If the separator is found, returns a 3-tuple containing the part before the separator, the separator itself, and the part after it. If the separator is not found, returns a 3-tuple containing two empty strings and the original string.
rsplit(self, /, sep=None, maxsplit=-1)
Return a list of the words in the string, using sep as the delimiter string.
sep
The delimiter according which to split the string.
None (the default value) means split according to any whitespace,
and discard empty strings from the result.
maxsplit
Maximum number of splits to do.
-1 (the default value) means no limit.
Splits are done starting at the end of the string and working to the front.
rstrip(self, chars=None, /) Return a copy of the string with trailing whitespace removed. If chars is given and not None, remove characters in chars instead.
split(self, /, sep=None, maxsplit=-1)
Return a list of the words in the string, using sep as the delimiter string.
sep
The delimiter according which to split the string.
None (the default value) means split according to any whitespace,
and discard empty strings from the result.
maxsplit
Maximum number of splits to do.
-1 (the default value) means no limit.
splitlines(self, /, keepends=False) Return a list of the lines in the string, breaking at line boundaries. Line breaks are not included in the resulting list unless keepends is given and true.
startswith(...) S.startswith(prefix[, start[, end]]) -> bool Return True if S starts with the specified prefix, False otherwise. With optional start, test S beginning at that position. With optional end, stop comparing S at that position. prefix can also be a tuple of strings to try.
strip(self, chars=None, /) Return a copy of the string with leading and trailing whitespace removed. If chars is given and not None, remove characters in chars instead.
swapcase(self, /) Convert uppercase characters to lowercase and lowercase characters to uppercase.
title(self, /) Return a version of the string where each word is titlecased. More specifically, words start with uppercased characters and all remaining cased characters have lower case.
translate(self, table, /)
Replace each character in the string using the given translation table.
table
Translation table, which must be a mapping of Unicode ordinals to
Unicode ordinals, strings, or None.
The table must implement lookup/indexing via __getitem__, for instance a
dictionary or list. If this operation raises LookupError, the character is
left untouched. Characters mapped to None are deleted.
upper(self, /) Return a copy of the string converted to uppercase.
zfill(self, width, /) Pad a numeric string with zeros on the left, to fill a field of the given width. The string is never truncated.
allocate_lock(...) allocate_lock() -> lock object (allocate() is an obsolete synonym) Create a new lock object. See help(type(threading.Lock())) for information about locks.