Xref: news2.mv.net comp.os.msdos.djgpp:8371
From: "John M. Aldrich" <fighteer AT cs DOT com>
Newsgroups: comp.os.msdos.djgpp
Subject: Re: version 2 problem
Date: Fri, 06 Sep 1996 18:42:13 -0700
Organization: Three pounds of chaos and a pinch of salt
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Message-ID: <3230D2F5.A0A@cs.com>
References: <199609061304 DOT NAA12912 AT hassrvares DOT er DOT usgs DOT gov>
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To: "<\"R. Steven Regan, Hydrologist, Reston, VA \"" <rsregan AT usgs DOT gov>
DJ-Gateway: from newsgroup comp.os.msdos.djgpp

<"R. Steven Regan, Hydrologist, Reston, VA " wrote:
> 
> Hello again, I noticed there were two copies of math.h (one in include and the
> other in include/libm).  I mv'd the one in libm into include and recompiled and
> was able to get the program working.  However, the results of the model are
> different under version 2 than under version 1 for some of the test cases.  This
> is very disturbing.  Also, I get a message "Extended error 183" occassionally.
> By this I mean, I will run the program on one test and get the message, then
> run it on another test and not get the message, then run the first test again
> and not get the message OR I could run one test and not get the message then
> run it again and get the message.  Note, I am using a Gateway 2000 P5-120 under
> Windows 95, using a DOS window to run the geochemical model.
> 
> I noticed there are other duplicate header file names in the include directory
> structure.
> 
> file.h  libc/file.h    sys/file.h
> pc.h    inlines/pc.h
> dir.h   sys/dir.h
> errno.h sys/errno.h
> time.h  sys/time.h
> 
> Apparently, the correct math.h was not getting included, so I am wondering if
> the correct versions of other header files are getting included.  I assume
> I should put back the original math.h, but how do I make sure the math.h in
> libm is used?

I believe the duplicate headers are a result of compatibility issues between
DJGPP and other compilers.  DJGPP was designed to compile code from as many
different compilers as possible, so I would guess that the multiple headers
are for compatibility with compilers which have conflicting versions.  As far
as how to include one of the alternate headers, simply do something like this:

#include <libm/math.h>

Directory separators are fine in #include directives.

There have been some problems using the original libm.a from djgpp v2, namely
occasional accuracy errors and inexplicable crashes.  Bug fixes have been
made and will be published in the next version of djgpp; meanwhile your best
bet is to either compile with the standard math functions (i.e., don't link
libm), or download a patched version from:

ftp://ftp.lstm.ruhr-uni-bochum.de/pub/djgpp/libm.zip

There is another ftp site that also has the same file.  Alternatively, I could
email you the uuencoded zipfile.

Hope this helps!

John <fighteer AT cs DOT com>

-- 
                      Anything that happens, happens.
    Anything that, in happening, causes something else to happen, causes
                         something else to happen.
 Anything that, in happening, causes itself to happen again, happens again.
        It doesn't necessarily do it in chronological order, though.
 
                                       --- Douglas Adams