Building applications

Table of Contents

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 the Compiling GLFW guide.

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

In the source files of your application where you use OpenGL or GLFW, you should include the GLFW header file, i.e.:

#include <GLFW/glfw3.h>

The GLFW header declares the GLFW API and by default also includes the OpenGL header of your development environment, which in turn defines all the constants, types and function prototypes of the OpenGL API.

The GLFW header also defines everything necessary for your OpenGL header to function. For example, under Windows you are normally required to include windows.h before the OpenGL header, which would pollute your code namespace with the entire Win32 API.

Instead, the GLFW header takes care of this for you, not by including windows.h, but by duplicating only the very few necessary parts of it. It does this only when needed, so if windows.h is included, the GLFW header does not try to redefine those symbols. The reverse is not true, i.e. windows.h cannot cope if any of its symbols have already been defined.

In other words:

If you are using an OpenGL extension loading library such as glad, the extension loader header should either be included before the GLFW one, or the GLFW_INCLUDE_NONE macro (described below) should be defined.

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.

GLFW_INCLUDE_GLCOREARB makes the GLFW header include the modern GL/glcorearb.h header (OpenGL/gl3.h on OS X) 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_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 OS X) is included.

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_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
GLFW does not provide any of the API headers mentioned above. They must be provided by your development environment or your OpenGL or OpenGL ES SDK.
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 OS X, 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 linking an application under Windows that uses the static version of GLFW, you must link with opengl32. On some versions of MinGW, you must also explicitly link with gdi32, while other versions of MinGW include it in the set of default libraries along with other dependencies like user32 and kernel32. If you are using GLU, you must also link with glu32.

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.

An application using the GLFW DLL does not need to link against any of its dependencies, but you still have to link against opengl32 if your application uses OpenGL and glu32 if it uses GLU.

With CMake and GLFW source

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

Firstly, add the root directory of the GLFW source tree to your project. This will add the glfw target and the necessary cache variables to your project.

add_subdirectory(path/to/glfw)

To be able to include the GLFW header from your code, you need to tell the compiler where to find it.

include_directories(path/to/glfw/include)

Once GLFW has been added to the project, the GLFW_LIBRARIES cache variable contains all link-time dependencies of GLFW as it is currently configured. To link against GLFW, link against them and the glfw target.

target_link_libraries(myapp glfw ${GLFW_LIBRARIES})

Note that GLFW_LIBRARIES does not include GLU, as GLFW does not use it. If your application needs GLU, you can add it to the list of dependencies with the OPENGL_glu_LIBRARY cache variable, which is implicitly created when the GLFW CMake files look for OpenGL.

target_link_libraries(myapp glfw ${OPENGL_glu_LIBRARY} ${GLFW_LIBRARIES})

With CMake on Unix and installed GLFW binaries

CMake can import settings from pkg-config, which GLFW supports. When you installed GLFW, the pkg-config file glfw3.pc was installed along with it.

First you need to find the PkgConfig package. If this fails, you may need to install the pkg-config package for your distribution.

find_package(PkgConfig REQUIRED)

This creates the CMake commands to find pkg-config packages. Then you need to find the GLFW package.

pkg_search_module(GLFW REQUIRED glfw3)

This creates the CMake variables you need to use GLFW. To be able to include the GLFW header, you need to tell your compiler where it is.

include_directories(${GLFW_INCLUDE_DIRS})

You also need to link against the correct libraries. If you are using the shared library version of GLFW, use the GLFW_LIBRARIES variable.

target_link_libraries(simple ${GLFW_LIBRARIES})

If you are using the static library version of GLFW, use the GLFW_STATIC_LIBRARIES variable instead.

target_link_libraries(simple ${GLFW_STATIC_LIBRARIES})

With pkg-config on OS X or other Unix

GLFW supports pkg-config, and the glfw3.pc pkf-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, simply 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 GLU, as GLFW does not use it. On OS X, GLU is built into the OpenGL framework, so if you need GLU you don't need to do anything extra. If you need GLU and are using Linux or BSD, you should add the glu pkg-config module.

cc `pkg-config --cflags glfw3 glu` -o myprog myprog.c `pkg-config --libs glfw3 glu`

If you are using the static version of the GLFW library, make sure you don't link statically against GLU.

cc `pkg-config --cflags glfw3 glu` -o myprog myprog.c `pkg-config --static --libs glfw3` `pkg-config --libs glu`

With Xcode on OS X

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

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

With command-line on OS X

It is recommended that you use pkg-config when building from the command line on OS X. 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 -framework CoreVideo

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.

The OpenGL framework contains both the OpenGL and GLU APIs, so there is nothing special to do when using GLU. Also note that even though your machine may have libGL-style OpenGL libraries, they are for use with the X Window System and will not work with the OS X native version of GLFW.