From 18cf804d0b85c66ba27ed80a412f17097330d506 Mon Sep 17 00:00:00 2001
From: Leo Yuriev <leo@yuriev.ru>
Date: Fri, 26 May 2017 17:11:48 +0300
Subject: [PATCH] mdbx: add STATIC_ASSERT_MSG, refine STATIC_ASSERT.

---
 src/bits.h |  3 +++
 src/defs.h | 15 ++++++++++-----
 src/osal.c | 20 ++++++++++----------
 3 files changed, 23 insertions(+), 15 deletions(-)

diff --git a/src/bits.h b/src/bits.h
index 96967ff3..9aa76327 100644
--- a/src/bits.h
+++ b/src/bits.h
@@ -31,6 +31,9 @@
 /*----------------------------------------------------------------------------*/
 
 /* Should be defined before any includes */
+#ifndef _GNU_SOURCE
+#define _GNU_SOURCE 1
+#endif
 #ifndef _FILE_OFFSET_BITS
 #define _FILE_OFFSET_BITS 64
 #endif
diff --git a/src/defs.h b/src/defs.h
index 290a854d..79e65d44 100644
--- a/src/defs.h
+++ b/src/defs.h
@@ -368,15 +368,20 @@
 
 #define FIXME "FIXME: " __FILE__ ", " STRINGIFY(__LINE__)
 
-#ifndef STATIC_ASSERT
-#   if __STDC_VERSION__ >= 201112L
-#       define STATIC_ASSERT(expr, msg) _Static_assert(expr, msg)
+#ifndef STATIC_ASSERT_MSG
+#   if (defined(__STDC_VERSION__) && __STDC_VERSION__ >= 201112L) \
+          || __has_feature(c_static_assert)
+#       define STATIC_ASSERT_MSG(expr, msg) _Static_assert(expr, msg)
 #   elif defined(static_assert)
-#       define STATIC_ASSERT(expr, msg) static_assert(expr, msg)
+#       define STATIC_ASSERT_MSG(expr, msg) static_assert(expr, msg)
 #   else
-#       define STATIC_ASSERT(expr, msg) switch (0) {case 0:case (expr):;}
+#       define STATIC_ASSERT_MSG(expr, msg) switch (0) {case 0:case (expr):;}
 #   endif
 #endif /* STATIC_ASSERT */
 
+#ifndef STATIC_ASSERT
+#   define STATIC_ASSERT(expr) STATIC_ASSERT_MSG(expr, #expr)
+#endif
+
 /* *INDENT-ON* */
 /* clang-format on */
diff --git a/src/osal.c b/src/osal.c
index 7e98aa82..4b56be70 100644
--- a/src/osal.c
+++ b/src/osal.c
@@ -407,8 +407,8 @@ int mdbx_pread(mdbx_filehandle_t fd, void *buf, size_t bytes, uint64_t offset) {
     return (rc == MDBX_SUCCESS) ? /* paranoia */ ERROR_READ_FAULT : rc;
   }
 #else
-  STATIC_ASSERT(sizeof(off_t) >= sizeof(size_t),
-                "libmdbx requires 64-bit file I/O on 64-bit systems");
+  STATIC_ASSERT_MSG(sizeof(off_t) >= sizeof(size_t),
+                    "libmdbx requires 64-bit file I/O on 64-bit systems");
   ssize_t read = pread(fd, buf, bytes, offset);
   if (read < 0) {
     int rc = errno;
@@ -437,8 +437,8 @@ int mdbx_pwrite(mdbx_filehandle_t fd, const void *buf, size_t bytes,
   int rc;
   ssize_t written;
   do {
-    STATIC_ASSERT(sizeof(off_t) >= sizeof(size_t),
-                  "libmdbx requires 64-bit file I/O on 64-bit systems");
+    STATIC_ASSERT_MSG(sizeof(off_t) >= sizeof(size_t),
+                      "libmdbx requires 64-bit file I/O on 64-bit systems");
     written = pwrite(fd, buf, bytes, offset);
     if (likely(bytes == (size_t)written))
       return MDBX_SUCCESS;
@@ -465,8 +465,8 @@ int mdbx_pwritev(mdbx_filehandle_t fd, struct iovec *iov, int iovcnt,
   int rc;
   ssize_t written;
   do {
-    STATIC_ASSERT(sizeof(off_t) >= sizeof(size_t),
-                  "libmdbx requires 64-bit file I/O on 64-bit systems");
+    STATIC_ASSERT_MSG(sizeof(off_t) >= sizeof(size_t),
+                      "libmdbx requires 64-bit file I/O on 64-bit systems");
     written = pwritev(fd, iov, iovcnt, offset);
     if (likely(expected_written == (size_t)written))
       return MDBX_SUCCESS;
@@ -556,8 +556,8 @@ int mdbx_filesize(mdbx_filehandle_t fd, uint64_t *length) {
 #else
   struct stat st;
 
-  STATIC_ASSERT(sizeof(off_t) <= sizeof(uint64_t),
-                "libmdbx requires 64-bit file I/O on 64-bit systems");
+  STATIC_ASSERT_MSG(sizeof(off_t) <= sizeof(uint64_t),
+                    "libmdbx requires 64-bit file I/O on 64-bit systems");
   if (fstat(fd, &st))
     return errno;
 
@@ -574,8 +574,8 @@ int mdbx_ftruncate(mdbx_filehandle_t fd, uint64_t length) {
              ? MDBX_SUCCESS
              : mdbx_get_errno_checked();
 #else
-  STATIC_ASSERT(sizeof(off_t) >= sizeof(size_t),
-                "libmdbx requires 64-bit file I/O on 64-bit systems");
+  STATIC_ASSERT_MSG(sizeof(off_t) >= sizeof(size_t),
+                    "libmdbx requires 64-bit file I/O on 64-bit systems");
   return ftruncate(fd, length) == 0 ? MDBX_SUCCESS : errno;
 #endif
 }