Date: Fri, 12 Mar 2004 19:41:36 +0100 (CET) From: Stefan Farfeleder <stefan@fafoe.narf.at> To: FreeBSD-gnats-submit@FreeBSD.org Cc: stefan@fafoe.narf.at Subject: standards/64173: C99 requires some <math.h> macros to be constant expressions Message-ID: <20040312184136.CF74D480@wombat.fafoe.narf.at> Resent-Message-ID: <200403121850.i2CIoKP9071680@freefall.freebsd.org>
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>Number: 64173
>Category: standards
>Synopsis: C99 requires some <math.h> macros to be constant expressions
>Confidential: no
>Severity: non-critical
>Priority: low
>Responsible: freebsd-standards
>State: open
>Quarter:
>Keywords:
>Date-Required:
>Class: sw-bug
>Submitter-Id: current-users
>Arrival-Date: Fri Mar 12 10:50:20 PST 2004
>Closed-Date:
>Last-Modified:
>Originator: Stefan Farfeleder
>Release: FreeBSD 5.2-CURRENT i386
>Organization:
>Environment:
System: FreeBSD wombat.fafoe.narf.at 5.2-CURRENT FreeBSD 5.2-CURRENT #16: Tue Mar 2 19:09:53 CET 2004 stefan@wombat.fafoe.narf.at:/usr/home/stefan/freebsd/obj/usr/home/stefan/freebsd/src/sys/WOMBAT i386
>Description:
Quoting from ISO/IEC 9899:1999:
# 7.12 Mathematics <math.h>
# 3 The macro
# HUGE_VAL
# expands to a positive double constant expression, not necessarily representable as a
# float. The macros
# HUGE_VALF
# HUGE_VALL
# are respectively float and long double analogs of HUGE_VAL.191)
#
# 4 The macro
# INFINITY
# expands to a constant expression of type float representing positive or unsigned
# infinity, if available; else to a positive constant of type float that overflows at
# translation time.192)
#
# 5 The macro
# NAN
# is defined if and only if the implementation supports quiet NaNs for the float type. It
# expands to a constant expression of type float representing a quiet NaN.
These macros expand to the variables __infinity and __nan currently (defined in
src/lib/${ARCH}/gen/infinity.c), thus violating the requirement of being
constant expressions.
>How-To-Repeat:
This strictly conformant C99 program fails to compile:
$ cat test.c
#include <math.h>
double d = HUGE_VAL;
int main(void) {}
$ c99 test.c
test.c:2: error: initializer element is not constant
>Fix:
None yet.
>Release-Note:
>Audit-Trail:
>Unformatted:
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