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authorZack Weinberg <zackw@panix.com>2016-08-22 08:06:30 -0400
committerZack Weinberg <zackw@panix.com>2016-09-23 08:43:55 -0400
commitcb765808fbffca30a1c67cf01ffdce30f8e6df3e (patch)
tree018dee14ad5381453a9b10de4b41d7e9d667bb33 /misc
parent3a35923e97a6e6e67f95a59ba7e45be22b45cd0b (diff)
downloadglibc-cb765808fbffca30a1c67cf01ffdce30f8e6df3e.tar.gz
Installed-header hygiene (BZ#20366): Simple self-contained fixes.
Some headers did not include all of their prerequisite headers. * rpcsvc/nislib.h: Include rpcsvc/nis.h. * sysdeps/unix/sysv/linux/netrose/rose.h: Include sys/socket.h and netax25/ax25.h. <endian.h> only defines BYTE_ORDER, BIG_ENDIAN, LITTLE_ENDIAN, etc. under __USE_MISC; glibc's headers should use __BYTE_ORDER, __BIG_ENDIAN, __LITTLE_ENDIAN, etc. instead. * inet/netinet/icmp6.h, inet/netinet/ip6.h * resolv/arpa/nameser_compat.h: Use __BYTE_ORDER etc. instead of BYTE_ORDER etc. sys/types.h only conditionally defines caddr_t and clockid_t. * sysdeps/unix/sysv/linux/sys/quota.h: Use __caddr_t instead of caddr_t. * sysdeps/unix/sysv/linux/sys/timerfd.h: Use __clockid_t instead of clockid_t. Remove a #warning that was the sole actual problem with using sys/ipc.h without _GNU_SOURCE/_XOPEN_SOURCE. * sysvipc/sys/ipc.h: Remove unnecessary #warning. _LIBC, __USE_XOPEN2K8, and __STDC_VERSION__ are not always defined. It seems to me that _LIBC should not appear in installed headers, but avoiding that for argp specifically would require more surgery than feels appropriate for this patch set. It's possible that "#ifdef _LIBC" would be sufficient, but I wanted to be conservative. All three versions of bits/socket.h want to know whether __flexarr will produce a real flexible array member -- specifically, one that doesn't alter sizeof(the structure containing it). They were testing for this with a complicated #if condition that did not agree with sys/cdefs.h and that tripped -Wundef warnings under -std=c90. I added a new macro to sys/cdefs.h, __glibc_c99_flexarr_available, which reveals exactly what these headers want to know. I also took the opportunity to flatten the rather messy conditional nest defining __flexarr. * argp/argp.h: Check whether _LIBC is defined before expanding it. * posix/glob.h: Check whether __USE_XOPEN2K8 is defined instead of expanding it. * misc/sys/cdefs.h: Tidy up conditional nest defining __flexarr. Define __glibc_c99_flexarr_available to 1 when the compiler supports C99-compatible flexible array members, 0 otherwise. * sysdeps/unix/sysv/linux/bits/socket.h * sysdeps/mach/hurd/bits/socket.h * bits/socket.h: Use __glibc_c99_flexarr_available in definitions of struct cmsghdr and CMSG_DATA.
Diffstat (limited to 'misc')
-rw-r--r--misc/sys/cdefs.h30
1 files changed, 18 insertions, 12 deletions
diff --git a/misc/sys/cdefs.h b/misc/sys/cdefs.h
index 6e9b8403d7..935a94b466 100644
--- a/misc/sys/cdefs.h
+++ b/misc/sys/cdefs.h
@@ -153,21 +153,27 @@
# define __errordecl(name, msg) extern void name (void)
#endif
-/* Support for flexible arrays. */
-#if __GNUC_PREREQ (2,97)
-/* GCC 2.97 supports C99 flexible array members. */
+/* Support for flexible arrays.
+ Headers that should use flexible arrays only if they're "real"
+ (e.g. only if they won't affect sizeof()) should test
+ #if __glibc_c99_flexarr_available. */
+#if defined __STDC_VERSION__ && __STDC_VERSION__ >= 199901L
+# define __flexarr []
+# define __glibc_c99_flexarr_available 1
+#elif __GNUC_PREREQ (2,97)
+/* GCC 2.97 supports C99 flexible array members as an extension,
+ even when in C89 mode or compiling C++ (any version). */
# define __flexarr []
+# define __glibc_c99_flexarr_available 1
+#elif defined __GNUC__
+/* Pre-2.97 GCC did not support C99 flexible arrays but did have
+ an equivalent extension with slightly different notation. */
+# define __flexarr [0]
+# define __glibc_c99_flexarr_available 1
#else
-# ifdef __GNUC__
-# define __flexarr [0]
-# else
-# if defined __STDC_VERSION__ && __STDC_VERSION__ >= 199901L
-# define __flexarr []
-# else
/* Some other non-C99 compiler. Approximate with [1]. */
-# define __flexarr [1]
-# endif
-# endif
+# define __flexarr [1]
+# define __glibc_c99_flexarr_available 0
#endif