On Mon, 29 Jul 2013, David Chisnall wrote:
Author: theraven
Date: Mon Jul 29 08:32:13 2013
New Revision: 253764
URL: http://svnweb.freebsd.org/changeset/base/253764
Log:
Reenable the isnan(double) / isinf(double) declarations when targeting C89 +
SUSv2 mode.
This isn't reenabling. but breaks the isnan() and isinf() macros by
#undefing them.
Modified:
head/lib/msun/src/math.h
Modified: head/lib/msun/src/math.h
==============================================================================
--- head/lib/msun/src/math.h Mon Jul 29 08:08:43 2013 (r253763)
+++ head/lib/msun/src/math.h Mon Jul 29 08:32:13 2013 (r253764)
@@ -209,6 +209,21 @@ __inline_isnanl(__const long double __x)
return (__x != __x);
}
+/*
+ * Version 2 of the Single UNIX Specification (UNIX98) defined isnan() and
+ * isinf() as functions taking double. C99, and the subsequent POSIX revisions
+ * (SUSv3, POSIX.1-2001, define it as a macro that accepts any real floating
+ * point type. If we are targeting SUSv2 and C99 or C11 (or C++11) then we
+ * expose the newer definition, assuming that the language spec takes
+ * precedence over the operating system interface spec.
+ */
+#if __XSI_VISIBLE > 0 && __XSI_VISIBLE < 600 && __ISO_C_VISIBLE < 1999
+#undef isinf
+#undef isnan
+int isinf(double);
+int isnan(double);
+#endif
+
Old versions declared these functions by temporarily hiding the macro
definitions using parentheses, and also sorted the declarations differently
(into the __BSD_VISIBLE || __ISO_C_VISIBLE >= 1999 || __XSI_VISIBLE
section. The __ISO_C_VISIBLE part of that ifdef is not quite broken for
these functions, since although they aren't in C99, I think only
non-conforming code can use them as functions). If the above ifdef is
correct, then it is still unsorted. Other ifdefs for fine-grained
XSI ifdefs are sorted later, in ascending order on __XSI_VISIBLE.
The others are written with slightly unclear nested conditions for
__XSI_VISIBLE:
@ #if __BSD_VISIBLE || __XSI_VISIBLE
Boolean conditions. You obfuscate the boolean condition __XSI_VISIBLE
by writing it as __XSI_VISIBLE > 0.
@ double j0(double);
@ double j1(double);
@ double jn(int, double);
@ double y0(double);
@ double y1(double);
@ double yn(int, double);
@
@ #if __XSI_VISIBLE <= 500 || __BSD_VISIBLE
Now the same boolean condition for the __BSD_VISIBLE part (obfuscated by
writing the conditions in the opposite order), but a further restriction
for the __XSI_VISIBLE part. __XSI_VISIBLE <= 500 by itself would be
broken since it would be satisfied by __XSI_VISIBLE == 0 which means
non-XSI.
@ double gamma(double);
@ #endif
@
@ #if __XSI_VISIBLE <= 600 || __BSD_VISIBLE
As above, for a later XSI.
You obfuscate the version tests further using '<' instead of '<='. '< 600'
does make more sense than '<= 500', since if 5 and 6 represent major
releases then API changes should occur at 600 not at 501.
@ double scalb(double, double);
@ #endif
@ #endif /* __BSD_VISIBLE || __XSI_VISIBLE */
double acos(double);
double asin(double);
double atan(double);
Bruce
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