Miscellany

the errors I get are:bash-3.2$ makegcc -o testdyngl.exe testdyngl.cpp -g -O2 -I/usr/local/include/SDL -I/usr/include/mingw -mno-cygwin -Dmain=SDL_main -DHAVE_OPENGL -L/usr/local/lib -lmingw32 -lSDLmain -lSDL -mno-cygwin -mwindowstestdyngl.cpp: In function `void init_glfuncs(glfuncs*)':testdyngl.cpp:76: error: invalid conversion from `void*' to `void (*)(GLenum)'testdyngl.cpp:77: error: invalid conversion from `void*' to `void (*)()'testdyngl.cpp:78: error: invalid conversion from `void*' to `void (*)(GLfloat, GLfloat, GLfloat)'testdyngl.cpp:79: error: invalid conversion from `void*' to `void (*)(GLfloat, GLfloat, GLfloat, GLfloat)'testdyngl.cpp:80: error: invalid conversion from `void*' to `void (*)(GLbitfield)'testdyngl.cpp:81: error: invalid conversion from `void*' to `void (*)(GLenum)'testdyngl.cpp:82: error: invalid conversion from `void*' to `void (*)(GLenum)'testdyngl.cpp:83: error: invalid conversion from `void*' to `void (*)(GLubyte, GLubyte, GLubyte, GLubyte)'testdyngl.cpp:84: error: invalid conversion from `void*' to `void (*)(GLfloat)'testdyngl.cpp:85: error: invalid conversion from `void*' to `void (*)(GLenum, GLenum)'testdyngl.cpp:86: error: invalid conversion from `void*' to `void (*)(GLenum, GLenum)'testdyngl.cpp:87: error: invalid conversion from `void*' to `void (*)(GLenum)'testdyngl.cpp:88: error: invalid conversion from `void*' to `void (*)()'testdyngl.cpp:89: error: invalid conversion from `void*' to `void (*)(GLdouble, GLdouble, GLdouble, GLdouble, GLdouble, GLdouble)'testdyngl.cpp:90: error: invalid conversion from `void*' to `void (*)(GLfloat, GLfloat, GLfloat, GLfloat)'testdyngl.cpp:91: error: invalid conversion from `void*' to `void (*)(GLint, GLint, GLsizei, GLsizei)'testdyngl.cpp:92: error: invalid conversion from `void*' to `void (*)(GLenum, GLfloat)'make: *** [testdyngl.exe] Error 1next line is line #37void* get_funcaddr(const char* p){	void* f=SDL_GL_GetProcAddress(p);	if (f)	{		return f;	}	else	{		fprintf(stderr,"Unable to get function pointer for %s\n",p);		quit(1);	}	return NULL;}typedef struct{	void(APIENTRY*glBegin)(GLenum);	void(APIENTRY*glEnd)();	void(APIENTRY*glVertex3f)(GLfloat, GLfloat, GLfloat);	void(APIENTRY*glClearColor)(GLfloat, GLfloat, GLfloat, GLfloat);	void(APIENTRY*glClear)(GLbitfield);	void(APIENTRY*glDisable)(GLenum);	void(APIENTRY*glEnable)(GLenum);	void(APIENTRY*glColor4ub)(GLubyte,GLubyte,GLubyte,GLubyte);	void(APIENTRY*glPointSize)(GLfloat);	void(APIENTRY*glHint)(GLenum,GLenum);	void(APIENTRY*glBlendFunc)(GLenum,GLenum);	void(APIENTRY*glMatrixMode)(GLenum);	void(APIENTRY*glLoadIdentity)();	void(APIENTRY*glOrtho)(GLdouble,GLdouble,GLdouble,GLdouble,GLdouble,GLdouble);	void(APIENTRY*glRotatef)(GLfloat,GLfloat,GLfloat,GLfloat);	void(APIENTRY*glViewport)(GLint,GLint,GLsizei,GLsizei);	void(APIENTRY*glFogf)(GLenum,GLfloat);}glfuncs;void init_glfuncs(glfuncs* f){	f->glBegin=get_funcaddr("glBegin");	f->glEnd=get_funcaddr("glEnd");	f->glVertex3f=get_funcaddr("glVertex3f");	f->glClearColor=get_funcaddr("glClearColor");	f->glClear=get_funcaddr("glClear");	f->glDisable=get_funcaddr("glDisable");	f->glEnable=get_funcaddr("glEnable");	f->glColor4ub=get_funcaddr("glColor4ub");	f->glPointSize=get_funcaddr("glPointSize");	f->glHint=get_funcaddr("glHint");	f->glBlendFunc=get_funcaddr("glBlendFunc");	f->glMatrixMode=get_funcaddr("glMatrixMode");	f->glLoadIdentity=get_funcaddr("glLoadIdentity");	f->glOrtho=get_funcaddr("glOrtho");	f->glRotatef=get_funcaddr("glRotatef");	f->glViewport=get_funcaddr("glViewport");	f->glFogf=get_funcaddr("glFogf");}