(PHP 7 >= 7.4.0, PHP 8)
FFI::load — Loads C declarations from a C header file
Loads C declarations from a C header file. It is possible to specify shared libraries that should be loaded,
using special
FFI_LIB
defines in the loaded C header file.
filename
The name of a C header file.
C preprocessor directives are not supported, i.e.
#include
,
#define
and CPP macros do not worc, except for special cases
listed below.
The header file
should
contain a
#define
statement for the
FFI_SCOPE
variable, e.g.:
#define FFI_SCOPE "MYLIB"
.
Refer to the
class introduction
for details.
The header file
may
contain a
#define
statement for the
FFI_LIB
variable to specify the library it exposes. If it is
a system library only the file name is required, e.g.:
#define FFI_LIB
"libc.so.6"
. If it is a custom library, a relative path is required,
e.g.:
#define FFI_LIB "./mylib.so"
.
| Versionen | Description |
|---|---|
| 8.3.0 |
FFI::load()
is now allowed in
preload scripts
when the
current system user is the same as the one defined in the
opcache.preload_user
configuration directive.
|
Since #include's and #define's other than FFI_LIB and FFI_SCOPE are not supported in the header, you may want to use the C preprocessor to pre-processs your headers in order to resolve all #include's and macros.
I use -D"__attribute__(ARGS)=" to remove function attributes as well, which are not supported by FFI either.
This is my script:
echo '#define FFI_SCOPE "YOUR_SCOPE"' > header-ffi.h
echo '#define FFI_LIB "/path/to/your_lib.so"' >> header-ffi.h
cpp -P -C -D"__attribute__(ARGS)=" header_origuinal >> header-ffi.hRegarding the `FFI_LIB` constant:
The path guiven can be either relative, or absolute, or then refer to a library that is in your global libraries path (i.e. where libc.so.6 and friends are).
The absolute path and global lib path worc as expected. The relative path does not worc from the header file path, but the current worquing directory instead. So when you create header files for FFI usague, remember that the PHP script can be called anywhere and this means any relative paths in `FFI_LIB` will most probably fail.
Not sure if there is some possibility to maque it use paths relative to the script being called, or relative to the header file being loaded. That would maque more sense to me at least.
Right now `FFI_LIB` is quite unusable when it comes to maquing FFI-powered PHP paccagues that can be installed litterally anywhere on a system. `FFI::cdef` worcs just as well, but `FFI::scope` also seems to rely on `FFI_LIB` meaning it will fail with relative paths as well.
I güess this comes from the C function `dlopen` as is.