The EGL_EXT_device_query extension introduces the
eglQueryDeviceStringEXT() function, which can be used with an
EGLDeviceEXT enumeration to receive an OpenGL extension string
containing all of the device extensions supported by it. From the
EGL_EXT_device_query spec's amendments to section "3.2 Devices" after
"3.1 Errors":
const char *eglQueryDeviceStringEXT(EGLDeviceEXT device,
EGLint name);
returns a pointer to a static, zero-terminated string describing
some aspect of the specified EGLDeviceEXT. <name> must be
EGL_EXTENSIONS.
Since OpenGL extension parsing is rather simple, and we could always run
into additional cases similar to this one in the future, we expose the
shared epoxy_extension_in_string() function in libepoxy's public headers
so that users can save themselves the hassle of having to write their
own extension parser.
Signed-off-by: Lyude Paul <thatslyude@gmail.com>
For the Visual Studio C compiler we need to annotate our public symbols
with `__declspec(dllimport)` to ensure they are visible when dynamically
linking to Epoxy's DLL.
This is needed because under Windows we use a dispatch table, instead of
wrapper functions, thus the symbol visibility rules change. Compiling
with MingW will automatically add `__declspec(dllimport)` for us.
Thanks to Nirbheek Chauhan for the help in debugging the issue.
Fixes#104
Older versions of the Microsoft Visual C compiler do not support C99 and
do not have stdbool.h.
Additionally, Epoxy is pretty much C89 compliant, and stdbool.h is part
of C99.
We can add a simple fallback for MSVC, in case we end up getting built
with it.
To avoid a symbols file on Windows, Epoxy annotates all the publicly
visible symbols directly in the source, but uses the default symbol
visibility everywhere else. This means that only some symbols are
annotated as `EPOXY_IMPORTEXPORT`, and generally only on Windows.
Additionally, Epoxy has a private 'PUBLIC' pre-processor macro for
internal use, which duplicates the `EPOXY_IMPORTEXPORT` but contains
more logic to detect GCC, in case we're building with GCC on Windows.
This would be enough, except that EGL is also available on Windows,
which means we'd have to annotate the exported `epoxy_*` API inside
epoxy/egl.h as well. At that point, though, we should probably avoid
any confusion, and adopt a single symbol visibility policy across the
board.
This requires some surgery of the generated and common dispatch sources,
but cuts down the overall complexity:
- there is only one annotation, `EPOXY_PUBLIC`, used everywhere
- the annotation detection is done at Epoxy configuration time
- only annotated symbols are public, on every platform
- annotated symbols are immediately visible from the header
We're going to use this header to provide shared macros. Right now, we
can use it to replace the:
#ifdef __cplusplus
extern "C" {
#endif
…
#ifdef __cplusplus
}
#endif
Stanzas for every installed header, with easier to read macros in the
same spirit of Cairo and GLib.
Lyude Paul
Emmanuele Bassi
Eric Anholt