F03GL: How to use OpenGL Multitexture functions such as glActiveTexture(), glMultiTexCoord3f()

[nightcat]

I want to realize the multitexture graph in Intel oneAPI Fortran and VS 2023 by using F03GL (Fortran 2003 Interface to OpenGL) mixed programming of Fortran and C/C++ for my application.

In my program I tried to use OpenGL Multitexture functions such as glActiveTexture(), glMultiTexCoord3f(), glMultiTexCoord2f() which are defined in gl.h but not in OpenGL_gl.f90. So I create a interface to bind C language for these function (just like that in gltools.f90 for the function such as glGenBuffers(), glBindBuffer, and glBufferData()) in my Fortran program:

Interface

! glActiveTexture — select active texture unit

! void glActiveTexture (GLenum texture);

!  return  void

!  param   texture             TextureUnit in value

SUBROUTINE glActiveTexture (texture) BIND(C, name ="cglewActiveTexture")

                IMPORT                

                INTEGER(kind=GLenum), VALUE :: texture

END SUBROUTINE glActiveTexture

!

! void glClientActiveTexture (GLenum texture);

!  return  void

!  param   texture             TextureUnit in value

SUBROUTINE glClientActiveTexture (texture) BIND(C, name ="cglewClientActiveTexture ")

                IMPORT                

                INTEGER(kind=GLenum), VALUE :: texture

END SUBROUTINE glClientActiveTexture

!

! void glMultiTexCoord2f (GLenum target, GLfloat s, GLfloat t);

! return  void

! param   target                TextureUnit in value

! param   s               CoordF in value

! param   t                CoordF in value

SUBROUTINE glMultiTexCoord2f (target, s, t) BIND(C,NAME="cglewMultiTexCoord2f")

                IMPORT

                INTEGER(GLenum), VALUE :: target

                REAL(GLfloat), VALUE :: s, t

END SUBROUTINE glMultiTexCoord2f

!

! void glMultiTexCoord3f (GLenum target, GLfloat s, GLfloat t, GLfloat r);

!  return  void

!  param   target               TextureUnit in value

!  param   s              CoordF in value

!  param   t               CoordF in value

!  param   r               CoordF in value             

SUBROUTINE glMultiTexCoord3f (target, s, t, r)        BIND(C,NAME="cglewMultiTexCoord3f")

                IMPORT

                INTEGER(GLenum), VALUE :: target

                REAL(GLfloat), VALUE :: s, t, r

END SUBROUTINE glMultiTexCoord3f

Interface

I can compile and link my program successfully and create an executable exe file. But when running the exe file and going to any such function, glActiveTexture(), glMultiTexCoord3f(), or glMultiTexCoord2f(), it displays a severe error and immediately exits the application:

forrtl: severe (157): Program Exception - access violation

Image              PC                Routine            Line        Source

Now I don't know what happens and how to solve this problem in my Fortran program. Can any experienced expert or specialist help me about this?

Many thanks in advance!

MX