php-ffi-cpp-mingw64.md

PHP FFI - Using a C++ DLL with C bindings with MinGW-64

Requirements

• MinGW-64

Setup

On Windows:

• Download the 64-Bit version of MinGW for Windows from: https://github.com/niXman/mingw-builds-binaries/releases
• Filename: x86_64-13.2.0-release-win32-seh-msvcrt-rt_v11-rev1.7z
• Extract the 7-ZIP file to: c:\mingw64
• Add C:\mingw64\bin to the system PATH enviornment variable

Example DLL

To specify C linkage, specify extern "C" for your function declarations.

• https://learn.microsoft.com/en-us/cpp/build/exporting-cpp-functions-for-use-in-c-language-executables?view=msvc-170

File: example.cpp

extern "C" __declspec( dllexport ) int foo();

int foo() {
    return 123;
}

Compilation

g++ -shared -s -mwindows -Wl,--subsystem,windows -o example.dll example.cpp

The -Wl,--subsystem,windows isn't really necessary, but it's just conventional that DLLs have the Windows GUI subsystem specified in their PE header. Also note the -s switch is used to strip symbols from the DLL - you will probably want to do this only for release builds.

Optional: To specify a input directory for header files, just add the -I c:\path\to\include as parameter:

PHP FFI Usage

<?php

use FFI;

$ffi = FFI::cdef(
    'int foo();',
    'example.dll'
);

var_dump($ffi->foo());

Output:

int(123)

php-ffi-cpp.md

PHP FFI - Using a C++ DLL with C bindings

Requirements

• Visual Studio 2022 Community Edition (free)
• The C and C++ SDK of Visual Studio

Setup

Add C:\Program Files\Microsoft Visual Studio\2022\Community\VC\Tools\MSVC\14.38.33130\bin\Hostx64\x64 to the system PATH enviornemnt variable.

This is the location of cl.exe

cl.exe ist the C / C++ compiler for the console.

Example dll

To specify C linkage, specify extern "C" for your function declarations.

• https://learn.microsoft.com/en-us/cpp/build/exporting-cpp-functions-for-use-in-c-language-executables?view=msvc-170

File: example.cpp

extern "C" __declspec( dllexport ) int foo();

int foo() {
    return 123;
}

Compilation

Open "cmd" and run: "C:\Program Files\Microsoft Visual Studio\2022\Community\VC\Auxiliary\Build\vcvars64.bat" to register the env variables.

In the same cmd window run the following command to compile the cpp file into a dll.

cl.exe /D_USRDLL /D_WINDLL example.cpp /link /DLL /OUT:wrapper.dll

PHP FFI Usage

<?php

use FFI;

$ffi = FFI::cdef(
    'int foo();',
    'example.dll'
);

var_dump($ffi->foo());

Output:

int(123)