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libstdc++/7793: Problems with numeric_limits<long double>::min()
- From: Peter Schmid <schmid at snake dot iap dot physik dot tu-darmstadt dot de>
- To: gcc-gnats at gcc dot gnu dot org
- Date: Sat, 31 Aug 2002 23:06:14 +0200
- Subject: libstdc++/7793: Problems with numeric_limits<long double>::min()
>Number: 7793
>Category: libstdc++
>Synopsis: Problems with numeric_limits<long double>::min()
>Confidential: no
>Severity: serious
>Priority: medium
>Responsible: unassigned
>State: open
>Class: sw-bug
>Submitter-Id: net
>Arrival-Date: Sat Aug 31 14:16:00 PDT 2002
>Closed-Date:
>Last-Modified:
>Originator: Peter Schmid
>Release: 3.3 20020831 (experimental)
>Organization:
TU Darmstadt
>Environment:
System: Linux kiste 2.4.18 #8 Sat Mar 9 15:33:15 CET 2002 i686 unknown
Architecture: i686
GNU ld version 2.13.90.0.4 20020814
host: i686-pc-linux-gnu
build: i686-pc-linux-gnu
target: i686-pc-linux-gnu
configured with: ../gcc/configure --enable-shared --disable-nls --enable-threads=posix --enable-languages=c,c++,f77,objc --enable-__cxa_atexit
>Description:
The values obtained for the smallest long double obtained from
the numeric_limits facility and the float.h interface (LDBL_MIN) differ.
>How-To-Repeat:
source code tlimit.C
#include <float.h>
#include <limits>
#include <iostream>
int main()
{
long double ldbl_min = LDBL_MIN;
long double limits_ldbl_min = std::numeric_limits<long double>::min();
std::cout << "Are LDBL_MIN:" << ldbl_min
<< " and numeric_limits<long double>::min():"
<< limits_ldbl_min << " the same? ";
(ldbl_min == limits_ldbl_min) ?
(std::cout << "yes\n") : (std::cout << "no\n");
}
g++ -v -o tlimit tlimit.C -W -Wall
Reading specs from /usr/local/lib/gcc-lib/i686-pc-linux-gnu/3.3/specs
Configured with: ../gcc/configure --enable-shared --disable-nls --enable-threads=posix --enable-languages=c,c++,f77,objc --enable-__cxa_atexit
Thread model: posix
gcc version 3.3 20020831 (experimental)
/usr/local/lib/gcc-lib/i686-pc-linux-gnu/3.3/cc1plus -quiet -v -D__GNUC__=3 -D__GNUC_MINOR__=3 -D__GNUC_PATCHLEVEL__=0 -D_GNU_SOURCE tlimit.C -D__GNUG__=3 -quiet -dumpbase tlimit.C -auxbase tlimit -W -Wall -version -o /tmp/ccquKuGg.s
GNU C++ version 3.3 20020831 (experimental) (i686-pc-linux-gnu)
compiled by GNU C version 3.3 20020831 (experimental).
ignoring nonexistent directory "NONE/include"
ignoring nonexistent directory "/usr/local/i686-pc-linux-gnu/include"
#include "..." search starts here:
#include <...> search starts here:
/usr/local/include/c++/3.3
/usr/local/include/c++/3.3/i686-pc-linux-gnu
/usr/local/include/c++/3.3/backward
/usr/local/include
/usr/local/lib/gcc-lib/i686-pc-linux-gnu/3.3/include
/usr/include
End of search list.
/usr/local/lib/gcc-lib/i686-pc-linux-gnu/3.3/../../../../i686-pc-linux-gnu/bin/as -V -Qy -o /tmp/ccyqVmkU.o /tmp/ccquKuGg.s
GNU assembler version 2.13.90.0.4 (i686-pc-linux-gnu) using BFD version 2.13.90.0.4 20020814
/usr/local/lib/gcc-lib/i686-pc-linux-gnu/3.3/collect2 --eh-frame-hdr -m elf_i386 -dynamic-linker /lib/ld-linux.so.2 -o tlimit /usr/lib/crt1.o /usr/lib/crti.o /usr/local/lib/gcc-lib/i686-pc-linux-gnu/3.3/crtbegin.o -L/usr/local/lib/gcc-lib/i686-pc-linux-gnu/3.3 -L/usr/local/lib/gcc-lib/i686-pc-linux-gnu/3.3/../../../../i686-pc-linux-gnu/lib -L/usr/local/lib/gcc-lib/i686-pc-linux-gnu/3.3/../../.. /tmp/ccyqVmkU.o -lstdc++ -lm -lgcc_s -lgcc -lc -lgcc_s -lgcc /usr/local/lib/gcc-lib/i686-pc-linux-gnu/3.3/crtend.o /usr/lib/crtn.o
./tlimit
Are LDBL_MIN:3.3621e-4932 and numeric_limits<long double>::min():1.68105e-4932 the same? no
>Fix:
>Release-Note:
>Audit-Trail:
>Unformatted: