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Re: new module 'isnan-nolibm'
From: |
Eric Blake |
Subject: |
Re: new module 'isnan-nolibm' |
Date: |
Sat, 24 Feb 2007 19:42:10 -0700 |
User-agent: |
Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.8.0.9) Gecko/20061207 Thunderbird/1.5.0.9 Mnenhy/0.7.4.666 |
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According to Bruno Haible on 2/24/2007 7:08 PM:
> Cygwin: isnan() is a function, defined in cygwin.dll
No, on cygwin, isnan is a macro in <math.h> that wraps the internal
functions __isnan{,lf}, and the isnan entry point in cygwin1.dll exists
only for backwards compatibility for multi-year-old apps that were
compiled against cygwin prior to the POSIX compliance bug being fixed of
providing isnan only as a macro. And you still didn't catch my point that
on cygwin, you don't need -lm to get isnan() to work, whether or not it is
an exported function, since modern code should not be linking against the
entry point isnan on cygwin anyways. Checking AC_CHECK_FUNC([isnan]) is
wrong since POSIX does not guarantee that isnan is a function; instead,
you must check whether including <math.h> and using isnan() will link
correctly in the absence of -lm.
- --
Don't work too hard, make some time for fun as well!
Eric Blake address@hidden
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- Re: new module 'isnan-nolibm', (continued)
- Re: new module 'isnan-nolibm', Bruno Haible, 2007/02/24
- Re: new module 'isnan-nolibm', Ben Pfaff, 2007/02/24
- Re: new module 'isnan-nolibm', Jim Meyering, 2007/02/27
- Re: new module 'isnan-nolibm', Matthew Woehlke, 2007/02/27
- Re: new module 'isnan-nolibm', Jim Meyering, 2007/02/27
- Re: new module 'isnan-nolibm', Ben Pfaff, 2007/02/27
- Re: new module 'isnan-nolibm', Bruno Haible, 2007/02/27
Re: new module 'isnan-nolibm', Eric Blake, 2007/02/24
Re: new module 'isnan-nolibm', Daniel Jacobowitz, 2007/02/24