GLX create GL 4.x context with GLEW crashes glXChooseFBConfig - opengl

Question

I have problems creating a GL 4.x context using plain GLX and GLEW (1.12). All solutions I found here are not working for me.
What I am trying to do (and what I found in other questions): Create a 'base' GL context, call glewInit(), then create the proper GL 4.x context using glXCreateContextAttribsARB(...). This did not work for me, since glXChooseFBConfig keeps segfaulting.
I read that I have to call glxewInit first, but that didn't work. Building without GLEW_MX defined resulted in glxewInit not being available. Building with GLEW_MX defined resulted in the following compile error:
error: 'glxewGetContext' was not declared in this scope #define glxewInit() glxewContextInit(glxewGetContext())
note: in expansion of macro 'glewxInit' auto result = glxewInit()
When I ommit calling glxewInit() the application crashes when calling glXChooseFBConfig(...)
I am rather stuck here. What is the proper way to get a GL 4.x context using plain GLX? (I cannot use glfw or something similiar, I am working on a given application, and I get a Display pointer and a Window id to work with, the window is already there)

Answer 1

Thanks to the hint from Nicol I was able to fix the problem myself. Looking at the glfw code I did the following (might not apply to everyone).
Create a default / old-school GL context using the given Display pointer and Window id. I also call glXQueryExtension to check for proper glX support.
After creating the default context I call glewInit but created function pointers to glXChooseFBConfigSGIX 'by hand'. Don't really know why I had to use the SGIX Extension, didn't bother to take a deeper look.
This way I was able to get a proper FBConfig structure to call glXCreateContextAttribsARB and create a new context after destroying the old one
Et voilá, I get my working GL 4.x context
Thanks againg to Nicol, I don't know why I didn't think of looking at other code.
Here's my solution:
XMapWindow( m_X11View->m_pDisplay, m_X11View->m_hWindow );
XWindowAttributes watt;
XGetWindowAttributes( m_X11View->m_pDisplay, m_X11View->m_hWindow, &watt );
XVisualInfo temp;
temp.visualid = XVisualIDFromVisual(watt.visual);
int n;
XVisualInfo* visual = XGetVisualInfo( m_X11View->m_pDisplay, VisualIDMask, &temp, &n );
int n_elems = 0;
if (glXQueryExtension(m_X11View->m_pDisplay,NULL,NULL))
{
// create dummy base context to init glew, create proper 4.x context
m_X11View->m_GLXContext = glXCreateContext( m_X11View->m_pDisplay, visual, 0, true );
glXMakeCurrent( m_X11View->m_pDisplay, m_X11View->m_hWindow, m_X11View->m_GLXContext );
// some debug output stuff
std::cerr << "GL vendor: " << glGetString(GL_VENDOR) << std::endl;
std::cerr << "GL renderer: " << glGetString(GL_RENDERER) << std::endl;
std::cerr << "GL Version: " << glGetString(GL_VERSION) << std::endl;
std::cerr << "GLSL version: " << glGetString(GL_SHADING_LANGUAGE_VERSION) << std::endl;
int glx_version_major;
int glx_version_minor;
if (glXQueryVersion(m_X11View->m_pDisplay,&glx_version_major,&glx_version_minor))
{
if (ExtensionSupported(m_X11View->m_pDisplay,screen,"GLX_SGIX_fbconfig"))
{
int result = glewInit();
if (GLEW_OK==result)
{
std::cerr << "GLEW init successful" << std::endl;
PFNGLXGETFBCONFIGATTRIBSGIXPROC GetFBConfigAttribSGIX = (PFNGLXGETFBCONFIGATTRIBSGIXPROC)
glXGetProcAddress( (GLubyte*)"glXGetFBConfigAttribSGIX");
PFNGLXCHOOSEFBCONFIGSGIXPROC ChooseFBConfigSGIX = (PFNGLXCHOOSEFBCONFIGSGIXPROC)
glXGetProcAddress( (GLubyte*)"glXChooseFBConfigSGIX");
PFNGLXCREATECONTEXTWITHCONFIGSGIXPROC CreateContextWithConfigSGIX = (PFNGLXCREATECONTEXTWITHCONFIGSGIXPROC)
glXGetProcAddress( (GLubyte*)"glXCreateContextWithConfigSGIX");
PFNGLXGETVISUALFROMFBCONFIGSGIXPROC GetVisualFromFBConfigSGIX = (PFNGLXGETVISUALFROMFBCONFIGSGIXPROC)
glXGetProcAddress( (GLubyte*)"glXGetVisualFromFBConfigSGIX");
int gl_attribs[] = {
GLX_CONTEXT_MAJOR_VERSION_ARB, 4,
GLX_CONTEXT_MINOR_VERSION_ARB, 4,
GLX_CONTEXT_PROFILE_MASK_ARB, GLX_CONTEXT_CORE_PROFILE_BIT_ARB,
//GLX_CONTEXT_FLAGS_ARB, GLX_CONTEXT_DEBUG_BIT_ARB,
0
};
GLXFBConfigSGIX* configs = ChooseFBConfigSGIX( m_X11View->m_pDisplay, screen, NULL, &n_elems );
glXDestroyContext( m_X11View->m_pDisplay, m_X11View->m_GLXContext );
m_X11View->m_GLXContext = glXCreateContextAttribsARB( m_X11View->m_pDisplay, configs[0], 0, true, gl_attribs );
glXMakeCurrent( m_X11View->m_pDisplay, m_X11View->m_hWindow, m_X11View->m_GLXContext );
/*
glDebugMessageCallback( GLDebugLog, NULL );
// setup message control
// disable everything
// enable errors only
glDebugMessageControl( GL_DONT_CARE, GL_DONT_CARE, GL_DONT_CARE, 0, 0, GL_FALSE );
glDebugMessageControl( GL_DEBUG_SOURCE_API, GL_DEBUG_TYPE_ERROR, GL_DONT_CARE,
0, 0, GL_TRUE );
*/
}
else
{
std::cerr << "GLEW init failed: " << glewGetErrorString(result) << std::endl;
}
}
}
}