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* [Bug math/6794] New: ilogb() does not raise exceptions or set errno on domain errors
@ 2008-07-31 9:47 mtk dot manpages at gmail dot com
2008-07-31 9:49 ` [Bug math/6794] " mtk dot manpages at gmail dot com
2008-07-31 9:52 ` mtk dot manpages at gmail dot com
0 siblings, 2 replies; 3+ messages in thread
From: mtk dot manpages at gmail dot com @ 2008-07-31 9:47 UTC (permalink / raw)
To: glibc-bugs
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The POSIX.1 specification of ilogb() says:
==
Domain Error
The x argument is zero, NaN, or ±Inf, or the correct value is not
representable as an integer.
If the integer expression (math_errhandling & MATH_ERRNO) is non-zero, then
errno shall be set to [EDOM]. If the integer expression (math_errhandling &
MATH_ERREXCEPT) is non-zero, then the invalid floating-point exception shall be
raised
==
However, in all of the above cases, errno is not set on error, and in some of
the cases, no exceptions is raised. In all cases errno should be set to EDOM
and an FE_INVALID exception should be raised.
Background:
On error, many glibc math functions both set errno and raise an exception
(fetestexcept(3)). For example, the following function all do this: acos(),
asin(), cosh(), sinh(), acosh(), asinh(), exp(), exp2(), ldexp(), log(),
log10(), log2(). However, there is much inconsistency. Some functions raise an
exception, but don't set errno. Some functions set errno for some errors, but
not others. A few set errno, but don't raise an exception. This series of bug
reports documents deviations from what I consider the ideal: all functions
should BOTH set errno AND raise an exception for all errors.
All of these reports relate to tests on glibc 2.8 (as provided by SUSE 11.0).
--
Summary: ilogb() does not raise exceptions or set errno on domain
errors
Product: glibc
Version: unspecified
Status: NEW
Severity: normal
Priority: P2
Component: math
AssignedTo: aj at suse dot de
ReportedBy: mtk dot manpages at gmail dot com
CC: glibc-bugs at sources dot redhat dot com
http://sourceware.org/bugzilla/show_bug.cgi?id=6794
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* [Bug math/6794] ilogb() does not raise exceptions or set errno on domain errors
2008-07-31 9:47 [Bug math/6794] New: ilogb() does not raise exceptions or set errno on domain errors mtk dot manpages at gmail dot com
@ 2008-07-31 9:49 ` mtk dot manpages at gmail dot com
2008-07-31 9:52 ` mtk dot manpages at gmail dot com
1 sibling, 0 replies; 3+ messages in thread
From: mtk dot manpages at gmail dot com @ 2008-07-31 9:49 UTC (permalink / raw)
To: glibc-bugs
------- Additional Comments From mtk dot manpages at gmail dot com 2008-07-31 09:48 -------
Created an attachment (id=2856)
--> (http://sourceware.org/bugzilla/attachment.cgi?id=2856&action=view)
test program
Sample runs demonstrating problem. In no case is errno set. For the Inf and
-Inf cases, no exception is raised.
$ /tmp/mt_ilogb 0
errno == 0
fetestexcept() says: FE_INVALID FE_DIVBYZERO
ilogb(0.00000000000000000e+00)=-2147483648
0 FE_DIVBYZERO normal
$ /tmp/mt_ilogb nan
errno == 0
fetestexcept() says: FE_INVALID
ilogb(nan)=-2147483648
0 FE_INVALID normal
$ /tmp/mt_ilogb inf
errno == 0
fetestexcept() says:
ilogb(inf)=2147483647
0 0 normal
$ /tmp/mt_ilogb -- -inf
errno == 0
fetestexcept() says:
ilogb(-inf)=2147483647
0 0 normal
--
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* [Bug math/6794] ilogb() does not raise exceptions or set errno on domain errors
2008-07-31 9:47 [Bug math/6794] New: ilogb() does not raise exceptions or set errno on domain errors mtk dot manpages at gmail dot com
2008-07-31 9:49 ` [Bug math/6794] " mtk dot manpages at gmail dot com
@ 2008-07-31 9:52 ` mtk dot manpages at gmail dot com
1 sibling, 0 replies; 3+ messages in thread
From: mtk dot manpages at gmail dot com @ 2008-07-31 9:52 UTC (permalink / raw)
To: glibc-bugs
------- Additional Comments From mtk dot manpages at gmail dot com 2008-07-31 09:50 -------
Also, it is worth noting that log(), log2(), log10() do set errno and raise an
exception for the 0 and --inf cases.
--
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2008-07-31 9:47 [Bug math/6794] New: ilogb() does not raise exceptions or set errno on domain errors mtk dot manpages at gmail dot com
2008-07-31 9:49 ` [Bug math/6794] " mtk dot manpages at gmail dot com
2008-07-31 9:52 ` mtk dot manpages at gmail dot com
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