Hi everyone,
I recently installed g++ 2.95.2 on a linux system, and I am now
getting some compilation failures when compiling code which references
glu.h as per the latest CVS images.
More specifically, consider the following C++ code:
#include <GL/glu.h>
void foo(GLUquadricObj *qobj)
{
gluQuadricDrawStyle(qobj, GLU_FILL);
}
With g++ 2.91.66 (which is the one which comes with RedHat 6.1, I think),
you get:
$ g++ -c foo.C
foo.C: In function `void foo(struct GLUquadricObj *)':
foo.C:5: warning: conversion from `enum {anonymous}' to `enum GLenum'
$ g++ --version
egcs-2.91.66
But with 2.95.2, you now get an error:
$ g++ -c foo.C
foo.C: In function `void foo(GLUquadricObj *)':
foo.C:5: conversion from `enum {anonymous}' to `enum GLenum'
$ g++ --version
2.95.2
The problem is that gluQuadricDrawStyle and frieds is defined as:
GLUAPI void GLAPIENTRY gluQuadricDrawStyle( GLUquadricObj *quadObject,
GLenum drawStyle );
whereas GLU_FILL is defined as an anonymous enum:
enum {
...
GLU_FILL = 100012,
...
};
and g++ is refusing to cast an anonymous enum it a GLenum. I'm not
enough of a C++ language lawyer to tell if g++ is wrong or not,
but I suspect that since a lot of people using Mesa will also
want to run the "latest and greatest" g++, this could be a problem.
Note that moving the same pre-processed source to IRIX gets the
same error on the MIPSpro C++ compiler:
$ CC -c foo.C
"foo.C", line 20: error(1164): argument of type "enum <unnamed>" is
incompatible with parameter of type "GLenum"
gluQuadricDrawStyle(qobj, GLU_FILL);
^
1 error detected in the compilation of "foo.C".
Note that in IRIX, gl.h defines:
typedef unsigned int GLenum;
and glu.h defines:
#define GLU_FILL 100012
which is why you don't normally get these kinds of problem on that
platform.
I imagine that there is a good reason for using enums instead of
#defines in the the Mesa gl.h and glu.h?
JF
Jean-Francois Panisset [EMAIL PROTECTED]
Software Engineer
Discreet Logic
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