On 04/05/2018 18:00, Daniel P. Berrangé wrote: > There are two useful macros that can be defined before including > glib.h that are related to the min required glib version > > - GLIB_VERSION_MIN_REQUIRED > > When this is defined, if code uses an API that was deprecated > in this version, or older, a compiler warning will be emitted. > This alerts maintainers to update their code to whatever new > replacement API is now recommended best practice. > > - GLIB_VERSION_MAX_ALLOWED > > When this is defined, if code uses an API that was introduced > in a version that is newer than the declared version, a compiler > warning will be emitted. This alerts maintainers if new code > accidentally uses functionality that won't be available on some > supported platforms. > > The GLIB_VERSION_MAX_ALLOWED constant makes it a bit harder to opt > in to using specific new APIs with a GLIB_CHECK_VERSION conditional. > To workaround this Pragmas can be used to temporarily turn off the > -Wdeprecated-declarations compiler warning, while a static inline > compat function is implemented. Nothing needs that at this time, > so just illustrate it in a comment for benefit of future changes.
Unfortunately there is one need, and it's a bug in glib itself: In file included from /usr/lib64/glib-2.0/include/glibconfig.h:9:0, from /usr/include/glib-2.0/glib/gtypes.h:32, from /usr/include/glib-2.0/glib/galloca.h:32, from /usr/include/glib-2.0/glib.h:30, from /home/pbonzini/work/upstream/qemu/include/glib-compat.h:29, from /home/pbonzini/work/upstream/qemu/include/qemu/osdep.h:107, from /home/pbonzini/work/upstream/qemu/disas/arm-a64.cc:21: /usr/include/glib-2.0/glib/glib-autocleanups.h: In function ‘void glib_autoptr_cleanup_GOptionGroup(GOptionGroup**)’: /usr/include/glib-2.0/glib/glib-autocleanups.h:63:45: error: ‘void g_option_group_unref(GOptionGroup*)’ is deprecated (declared at /usr/include/glib-2.0/glib/goption.h:372): Not available before 2.44 [-Werror=deprecated-declarations] G_DEFINE_AUTOPTR_CLEANUP_FUNC(GOptionGroup, g_option_group_unref) ^ /usr/include/glib-2.0/glib/gmacros.h:444:88: note: in definition of macro ‘G_DEFINE_AUTOPTR_CLEANUP_FUNC’ static inline void _GLIB_AUTOPTR_FUNC_NAME(TypeName) (TypeName **_ptr) { if (*_ptr) (func) (*_ptr); } \ ^ /usr/include/glib-2.0/glib/gmacros.h:444:100: error: ‘void g_option_group_unref(GOptionGroup*)’ is deprecated (declared at /usr/include/glib-2.0/glib/goption.h:372): Not available before 2.44 [-Werror=deprecated-declarations] static inline void _GLIB_AUTOPTR_FUNC_NAME(TypeName) (TypeName **_ptr) { if (*_ptr) (func) (*_ptr); } \ ^ /usr/include/glib-2.0/glib/glib-autocleanups.h:63:1: note: in expansion of macro ‘G_DEFINE_AUTOPTR_CLEANUP_FUNC’ G_DEFINE_AUTOPTR_CLEANUP_FUNC(GOptionGroup, g_option_group_unref) (This is RHEL7 glib2-2.50.3-3.el7.x86_64). Luckily you suggested the solution yourself---this seems to work: diff --git a/include/glib-compat.h b/include/glib-compat.h index d066f6d..ef07489 100644 --- a/include/glib-compat.h +++ b/include/glib-compat.h @@ -26,6 +26,8 @@ */ #define GLIB_VERSION_MAX_ALLOWED GLIB_VERSION_2_42 +_Pragma("GCC diagnostic push") +_Pragma("GCC diagnostic ignored \"-Wdeprecated-declarations\"") #include <glib.h> /* @@ -42,8 +44,6 @@ * signature that does what we need, but with a "_qemu" * suffix eg * - * _Pragma("GCC diagnostic push") - * _Pragma("GCC diagnostic ignored \"-Wdeprecated-declarations\"") * static inline void g_foo_qemu(const char *wibble) * { * #if GLIB_CHECK_VERSION(X, Y, 0) @@ -52,12 +52,10 @@ * g_something_equivalent_in_older_glib(wibble); * #endif * } - * _Pragma("GCC diagnostic pop") * - * The Pragma calls turn off -Wdeprecated-declarations, - * ensuring this wrapper function impl doesn't trigger the - * compiler warning about using too new glib APIs. Finally - * we can do + * The _Pragma at the top of this file turns off -Wdeprecated-declarations, + * ensuring this wrapper function impl doesn't trigger the compiler warning + * about using too new glib APIs. Finally we can do * * #define g_foo(a) g_foo_qemu(a) * @@ -94,4 +92,6 @@ gint g_poll_fixed(GPollFD *fds, guint nfds, gint timeout); } while (0) #endif +_Pragma("GCC diagnostic pop") + #endif I'll give it a shot on clang too. Paolo