Add macros wrapping all usage of gcc's __attribute__.

Until now __attribute__() was defined to be empty for all compilers but
gcc. That's problematic because it prevents using it in other compilers;
which is necessary e.g. for atomics portability.  It's also just
generally dubious to do so in a header as widely included as c.h.

Instead add pg_attribute_format_arg, pg_attribute_printf,
pg_attribute_noreturn macros which are implemented in the compilers that
understand them. Also add pg_attribute_noreturn and pg_attribute_packed,
but don't provide fallbacks, since they can affect functionality.

This means that external code that, possibly unwittingly, relied on
__attribute__ defined to be empty on !gcc compilers may now run into
warnings or errors on those compilers. But there shouldn't be many
occurances of that and it's hard to work around...

Discussion: 54B58BA3.8040302@ohmu.fi
Author: Oskari Saarenmaa, with some minor changes by me.

1 files changed, 4 insertions, 4 deletions

diff --git a/src/bin/pg_dump/pg_backup_utils.h b/src/bin/pg_dump/pg_backup_utils.h
index 1bcc1a784fa..2e9a69a615d 100644
--- a/src/bin/pg_dump/pg_backup_utils.h
+++ b/src/bin/pg_dump/pg_backup_utils.h
@@ -30,15 +30,15 @@ extern const char *progname;
 extern void set_dump_section(const char *arg, int *dumpSections);
 extern void
 write_msg(const char *modulename, const char *fmt,...)
-__attribute__((format(PG_PRINTF_ATTRIBUTE, 2, 3)));
+pg_attribute_printf(2, 3);
 extern void
 vwrite_msg(const char *modulename, const char *fmt, va_list ap)
-__attribute__((format(PG_PRINTF_ATTRIBUTE, 2, 0)));
+pg_attribute_printf(2, 0);
 extern void on_exit_nicely(on_exit_nicely_callback function, void *arg);
-extern void exit_nicely(int code) __attribute__((noreturn));
+extern void exit_nicely(int code) pg_attribute_noreturn;
 
 extern void
 exit_horribly(const char *modulename, const char *fmt,...)
-__attribute__((format(PG_PRINTF_ATTRIBUTE, 2, 3), noreturn));
+pg_attribute_printf(2, 3) pg_attribute_noreturn;
 
 #endif   /* PG_BACKUP_UTILS_H */