FFI

The method creates a binding on the existing C function.

All variables and functions defined by first arguments are bound to corresponding native symbols in DSO library and then may be accessed as FFI object methods and properties. C types of argument, return value and variables are automatically converted to/from PHP types (if possible). Otherwise, they are wrapped in a special CData proxy object and may be accessed by elements.

Instead of embedding of a long C definition into PHP string, and creating FFI through FFI::cdef(), it's possible to separate it into a C header file. Note, that C preprocessor directives (e.g. #define or #ifdef) are not supported. And only a couple of special macros may be used especially for FFI.

 #define FFI_LIB "libc.so.6"

 int printf(const char *format, ...);

Here, FFI_LIB specifies, that the given library should be loaded.

 $ffi = FFI::load(__DIR__ . "/printf.h");
 $ffi->printf("Hello world!\n");

FFI definition parsing and shared library loading may take significant time. It's not useful to do it on each HTTP request in WEB environment. However, it's possible to pre-load FFI definitions and libraries at php startup, and instantiate FFI objects when necessary. Header files may be extended with FFI_SCOPE define (default pre-loading scope is "C"). This name is going to be used as FFI::scope() argument. It's possible to pre-load few files into a single scope.

 #define FFI_LIB "libc.so.6"
 #define FFI_SCOPE "libc"

 int printf(const char *format, ...);

These files are loaded through the same FFI::load() load function, executed from file loaded by opcache.preload php.ini directive.

 ffi.preload=/etc/php/ffi/printf.h

Finally, FFI::scope() instantiate an FFI object, that implements all C definition from the given scope.

 $ffi = FFI::scope("libc");
 $ffi->printf("Hello world!\n");

Method that creates an arbitrary C structure.

Manually removes previously created "not-owned" data structure.

Casts given $pointer to another C type, specified by C declaration string or FFI\CType object.

This function may be called statically and use only predefined types, or as a method of previously created FFI object. In last case the first argument may reuse all type and tag names defined in FFI::cdef().

This function creates and returns a FFI\CType object, representng type of the given C type declaration string.

FFI::type() may be called statically and use only predefined types, or as a method of previously created FFI object. In last case the first argument may reuse all type and tag names defined in FFI::cdef().

This function returns the FFI\CType object, representing the type of the given FFI\CData object.

Constructs a new C array type with elements of $type and dimensions specified by $dimensions.

Returns C pointer to the given C data structure. The pointer is not "owned" and won't be free. Anyway, this is a potentially unsafe operation, because the life-time of the returned pointer may be longer than life-time of the source object, and this may cause dangling pointer dereference (like in regular C).

Returns size of C data type of the given FFI\CData or FFI\CType.

Returns size of C data type of the given FFI\CData or FFI\CType.

Copies $size bytes from memory area $source to memory area $target.

$source may be any native data structure (FFI\CData) or PHP string.

Compares $size bytes from memory area $ptr1 and $ptr2.

Fills the $size bytes of the memory area pointed to by $target with the constant byte $byte.

Creates a PHP string from $size bytes of memory area pointed by $source. If size is omitted, $source must be zero terminated array of C chars.

Checks whether the FFI\CData is a null pointer.