limits.h defines {FLT,DBL}_{MAX,MIN} macros, even though float.h is
supposed to do that. Those values are not exactly representable
double/float as the specification mandates and the patched gcc treats
them in extended precision (in violation of C99), which breaks code
(e.g. in vf_fps) like
double f = DBL_MAX;
[...]
if (f == DBL_MAX) { // f has not been changed yet
[....]
}
---
At Janne's suggestion, changed the detection method to a compile check instead
of hardcoding net/openbsd.
Fixed the description of the cause -- a patched gcc that violates the standard
also collaborates on the breakage.
---
compat/limits/limits.h | 41 +++++++++++++++++++++++++++++++++++++++++
configure | 14 ++++++++++++++
2 files changed, 55 insertions(+)
create mode 100644 compat/limits/limits.h
diff --git a/compat/limits/limits.h b/compat/limits/limits.h
new file mode 100644
index 0000000..0ebe08d
--- /dev/null
+++ b/compat/limits/limits.h
@@ -0,0 +1,41 @@
+/*
+ * Work around a broken combination of the limits.h header and gcc on some BSD
+ * flavors.
+ *
+ * This file is part of Libav.
+ *
+ * Libav is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * Libav is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with Libav; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#ifndef LIBAV_COMPAT_BSD_LIMITS_H
+#define LIBAV_COMPAT_BSD_LIMITS_H
+
+#include_next <limits.h>
+
+#ifdef FLT_MAX
+#undef FLT_MAX
+#define FLT_MAX 3.40282346638528859812e+38F
+
+#undef FLT_MIN
+#define FLT_MIN 1.17549435082228750797e-38F
+
+#undef DBL_MAX
+#define DBL_MAX ((double)1.79769313486231570815e+308L)
+
+#undef DBL_MIN
+#define DBL_MIN ((double)2.22507385850720138309e-308L)
+#endif
+
+#endif /* LIBAV_COMPAT_BSD_LIMITS_H */
diff --git a/configure b/configure
index 84ee548..c685e8d 100755
--- a/configure
+++ b/configure
@@ -963,6 +963,16 @@ check_builtin(){
check_code ld "$headers" "$builtin" "$@" && enable "$name"
}
+check_compile_assert(){
+ log check_compile_assert "$@"
+ name=$1
+ headers=$2
+ condition=$3
+ shift 3
+ disable "$name"
+ check_code cc "$headers" "char c[!!($condition) - 1]" "$@" && enable
"$name"
+}
+
require(){
name="$1"
header="$2"
@@ -1286,6 +1296,7 @@ HAVE_LIST="
fast_clz
fast_cmov
fcntl
+ flt_lim
fork
getaddrinfo
gethrtime
@@ -3393,6 +3404,9 @@ if enabled_all ccc glibc; then
add_ldflags -Wl,-z,now # calls to libots crash without this
fi
+check_compile_assert flt_lim "float.h limits.h" "DBL_MAX == (double)DBL_MAX" ||
+ add_cppflags '-I\$(SRC_PATH)/compat/limits'
+
esc(){
echo "$*" | sed 's/%/%25/g;s/:/%3a/g'
}
--
1.7.10.4
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