GLFW: Building applications

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Building applications

This is about compiling and linking applications that use GLFW. For information on how to write such applications, start with the introductory tutorial. For information on how to compile the GLFW library itself, see Compiling GLFW.

This is not a tutorial on compilation or linking. It assumes basic understanding of how to compile and link a C program as well as how to use the specific compiler of your chosen development environment. The compilation and linking process should be explained in your C programming material and in the documentation for your development environment.

# Including the GLFW header file

You should include the GLFW header in the source files where you use OpenGL or GLFW.

#include <GLFW/glfw3.h>
glfw3.h
The header of the GLFW 3 API.

This header defines all the constants and declares all the types and function prototypes of the GLFW API. By default it also includes the OpenGL header from your development environment. See option macros below for how to select OpenGL ES headers and more.

The GLFW header also defines any platform-specific macros needed by your OpenGL header, so that it can be included without needing any window system headers.

It does this only when needed, so if window system headers are included, the GLFW header does not try to redefine those symbols. The reverse is not true, i.e. `windows.h` cannot cope if any Win32 symbols have already been defined.

In other words:

- Use the GLFW header to include OpenGL or OpenGL ES headers portably
- Do not include window system headers unless you will use those APIs directly
- If you do need such headers, include them before the GLFW header

If you are using an OpenGL extension loading library such as glad, the extension loader header should be included before the GLFW one. GLFW attempts to detect any OpenGL or OpenGL ES header or extension loader header included before it and will then disable the inclusion of the default OpenGL header. Most extension loaders also define macros that disable similar headers below it.

#include <glad/gl.h>
#include <GLFW/glfw3.h>

Both of these mechanisms depend on the extension loader header defining a known macro. If yours doesn't or you don't know which one your users will pick, the GLFW_INCLUDE_NONE macro will explicitly to prevent the GLFW header from including the OpenGL header. This will also allow you to include the two headers in any order.

#define GLFW_INCLUDE_NONE
#include <GLFW/glfw3.h>
#include <glad/gl.h>

## GLFW header option macros

These macros may be defined before the inclusion of the GLFW header and affect its behavior.

GLFW_DLL is required on Windows when using the GLFW DLL, to tell the compiler that the GLFW functions are defined in a DLL.

The following macros control which OpenGL or OpenGL ES API header is included. Only one of these may be defined at a time.

Note
  GLFW does not provide any of the API headers mentioned below. They are provided by your development environment or your OpenGL, OpenGL ES or Vulkan SDK, and most of them can be downloaded from the Khronos Registry.

GLFW_INCLUDE_GLCOREARB makes the GLFW header include the modern `GL/glcorearb.h` header (`OpenGL/gl3.h` on macOS) instead of the regular OpenGL header.

GLFW_INCLUDE_ES1 makes the GLFW header include the OpenGL ES 1.x `GLES/gl.h` header instead of the regular OpenGL header.

GLFW_INCLUDE_ES2 makes the GLFW header include the OpenGL ES 2.0 `GLES2/gl2.h` header instead of the regular OpenGL header.

GLFW_INCLUDE_ES3 makes the GLFW header include the OpenGL ES 3.0 `GLES3/gl3.h` header instead of the regular OpenGL header.

GLFW_INCLUDE_ES31 makes the GLFW header include the OpenGL ES 3.1 `GLES3/gl31.h` header instead of the regular OpenGL header.

GLFW_INCLUDE_ES32 makes the GLFW header include the OpenGL ES 3.2 `GLES3/gl32.h` header instead of the regular OpenGL header.

GLFW_INCLUDE_NONE makes the GLFW header not include any OpenGL or OpenGL ES API header. This is useful in combination with an extension loading library.

If none of the above inclusion macros are defined, the standard OpenGL `GL/gl.h` header (`OpenGL/gl.h` on macOS) is included, unless GLFW detects the inclusion guards of any OpenGL, OpenGL ES or extension loader header it knows about.

The following macros control the inclusion of additional API headers. Any number of these may be defined simultaneously, and/or together with one of the above macros.

GLFW_INCLUDE_VULKAN makes the GLFW header include the Vulkan `vulkan/vulkan.h` header in addition to any selected OpenGL or OpenGL ES header.

GLFW_INCLUDE_GLEXT makes the GLFW header include the appropriate extension header for the OpenGL or OpenGL ES header selected above after and in addition to that header.

GLFW_INCLUDE_GLU makes the header include the GLU header in addition to the header selected above. This should only be used with the standard OpenGL header and only for compatibility with legacy code. GLU has been deprecated and should not be used in new code.

Note
  None of these macros may be defined during the compilation of GLFW itself. If your build includes GLFW and you define any these in your build files, make sure they are not applied to the GLFW sources.

# Link with the right libraries

GLFW is essentially a wrapper of various platform-specific APIs and therefore needs to link against many different system libraries. If you are using GLFW as a shared library / dynamic library / DLL then it takes care of these links. However, if you are using GLFW as a static library then your executable will need to link against these libraries.

On Windows and macOS, the list of system libraries is static and can be hard-coded into your build environment. See the section for your development environment below. On Linux and other Unix-like operating systems, the list varies but can be retrieved in various ways as described below.

A good general introduction to linking is Beginner's Guide to Linkers by David Drysdale.

## With MinGW or Visual C++ on Windows

The static version of the GLFW library is named `glfw3`. When using this version, it is also necessary to link with some libraries that GLFW uses.

When using MinGW to link an application with the static version of GLFW, you must also explicitly link with `gdi32`. Other toolchains including MinGW-w64 include it in the set of default libraries along with other dependencies like `user32` and `kernel32`.

The link library for the GLFW DLL is named `glfw3dll`. When compiling an application that uses the DLL version of GLFW, you need to define the GLFW_DLL macro before any inclusion of the GLFW header. This can be done either with a compiler switch or by defining it in your source code.

## With CMake and GLFW source

This section is about using CMake to compile and link GLFW along with your application. If you want to use an installed binary instead, see With CMake and installed GLFW binaries.

With a few changes to your `CMakeLists.txt` you can have the GLFW source tree built along with your application.

When including GLFW as part of your build, you probably don't want to build the GLFW tests, examples and documentation. To disable these, set the corresponding cache variables before adding the GLFW source tree.

set(GLFW_BUILD_DOCS OFF CACHE BOOL "" FORCE)
set(GLFW_BUILD_TESTS OFF CACHE BOOL "" FORCE)
set(GLFW_BUILD_EXAMPLES OFF CACHE BOOL "" FORCE)

Add the root directory of the GLFW source tree to your project. This will add the `glfw` target to your project.

add_subdirectory(path/to/glfw)

Once GLFW has been added, link your application against the `glfw` target. This adds the GLFW library and its link-time dependencies as it is currently configured, the include directory for the GLFW header and, when applicable, the GLFW_DLL macro.

target_link_libraries(myapp glfw)

Note that the `glfw` target does not depend on OpenGL, as GLFW loads any OpenGL, OpenGL ES or Vulkan libraries it needs at runtime. If your application calls OpenGL directly, instead of using a modern extension loader library, use the OpenGL CMake package.

find_package(OpenGL REQUIRED)

If OpenGL is found, the `OpenGL::GL` target is added to your project, containing library and include directory paths. Link against this like any other library.

target_link_libraries(myapp OpenGL::GL)

For a minimal example of a program and GLFW sources built with CMake, see the GLFW CMake Starter on GitHub.

## With CMake and installed GLFW binaries

This section is about using CMake to link GLFW after it has been built and installed. If you want to build it along with your application instead, see With CMake and GLFW source.

With a few changes to your `CMakeLists.txt` you can locate the package and target files generated when GLFW is installed.

find_package(glfw3 3.3 REQUIRED)

Once GLFW has been added to the project, link against it with the `glfw` target. This adds the GLFW library and its link-time dependencies, the include directory for the GLFW header and, when applicable, the GLFW_DLL macro.

target_link_libraries(myapp glfw)

Note that the `glfw` target does not depend on OpenGL, as GLFW loads any OpenGL, OpenGL ES or Vulkan libraries it needs at runtime. If your application calls OpenGL directly, instead of using a modern extension loader library, use the OpenGL CMake package.

find_package(OpenGL REQUIRED)

If OpenGL is found, the `OpenGL::GL` target is added to your project, containing library and include directory paths. Link against this like any other library.

target_link_libraries(myapp OpenGL::GL)

## With makefiles and pkg-config on Unix

GLFW supports pkg-config, and the `glfw3.pc` pkg-config file is generated when the GLFW library is built and is installed along with it. A pkg-config file describes all necessary compile-time and link-time flags and dependencies needed to use a library. When they are updated or if they differ between systems, you will get the correct ones automatically.

A typical compile and link command-line when using the static version of the GLFW library may look like this:

cc $(pkg-config --cflags glfw3) -o myprog myprog.c $(pkg-config --static --libs glfw3)

If you are using the shared version of the GLFW library, omit the `--static` flag.

cc $(pkg-config --cflags glfw3) -o myprog myprog.c $(pkg-config --libs glfw3)

You can also use the `glfw3.pc` file without installing it first, by using the `PKG_CONFIG_PATH` environment variable.

env PKG_CONFIG_PATH=path/to/glfw/src cc $(pkg-config --cflags glfw3) -o myprog myprog.c $(pkg-config --libs glfw3)

The dependencies do not include OpenGL, as GLFW loads any OpenGL, OpenGL ES or Vulkan libraries it needs at runtime. If your application calls OpenGL directly, instead of using a modern extension loader library, you should add the `gl` pkg-config package.

cc $(pkg-config --cflags glfw3 gl) -o myprog myprog.c $(pkg-config --libs glfw3 gl)

## With Xcode on macOS

If you are using the dynamic library version of GLFW, add it to the project dependencies.

If you are using the static library version of GLFW, add it and the Cocoa, OpenGL and IOKit frameworks to the project as dependencies. They can all be found in `/System/Library/Frameworks`.

## With command-line on macOS

It is recommended that you use pkg-config when building from the command line on macOS. That way you will get any new dependencies added automatically. If you still wish to build manually, you need to add the required frameworks and libraries to your command-line yourself using the `-l` and `-framework` switches.

If you are using the dynamic GLFW library, which is named `libglfw.3.dylib`, do:

cc -o myprog myprog.c -lglfw -framework Cocoa -framework OpenGL -framework IOKit

If you are using the static library, named `libglfw3.a`, substitute `-lglfw3` for `-lglfw`.

Note that you do not add the `.framework` extension to a framework when linking against it from the command-line.

Note
  Your machine may have `libGL.*.dylib` style OpenGL library, but that is for the X Window System and will not work with the macOS native version of GLFW.