Re: [Openexr-devel] Couple of minor things...

[Florian Kainz]

darby johnston wrote:
> Hi,
>
> Found a couple minor things while using your excellent
> library:
>
> ImfStandardAttributes.h, line 146:
>
>   IMF_STD_ATTRIBUTE_DEF (utcOffset, utcOffset, float)
>
> The second argument should probably be capitalized to
> match the style of the rest of the standard
> attributes:
>
>   IMF_STD_ATTRIBUTE_DEF (utcOffset, UtcOffset, float)

Thank you for pointing this out.  I will change the
capitalization for utcOffset.  The change will not
affect the file format, but programs that call
add hasutcOfffset() or addutcOffset() will have to be
updated to call hasUtcOffset() or addUtcOffset() instead.

> Also, it looks like the document
> "ReadingAndWritingImageFiles.pdf" is slightly out of
> sync with the current code; in section "3.5 Which
> Channels are in a File?", the example uses iterators
> like:
>
>   for (ChannelList::ConstIterator i =
> channels.begin(); i != channels.end(); ++i)
>   {
>       const Channel &channel = i->second;
>       // ...
>   }
>
> But the iterators have changed their access methods,
> so the above should read:
>
>   for (ChannelList::ConstIterator i =
> channels.begin(); i != channels.end(); ++i)
>   {
>       const Channel &channel = i.channel();
>       // ...
>   }

I have fixed the document.  I will have the corrected
version posted on the OpenEXR web site.

> When compiling OpenEXR under Solaris 10 6/06 with Sun
> Studio 11, I got an error about missing math symbols:
>
>   CC -G -zdefs -hlibImath.so.4 -o
> .libs/libImath.so.4.0.0   .libs/ImathShear.o
> .libs/ImathMatrixAlgo.o .libs/ImathVec.o
> .libs/ImathColorAlgo.o .libs/ImathFun.o
> .libs/ImathBox.o .libs/ImathRandom.o 
> -R/home/darby/pkg/tmp/openexr-1.4.0/Iex/.libs
> -R/home/darby/pkg/tmp/lib ../Iex/.libs/libIex.so
> -lposix4 -lpthread -lCstd -lCrun -lc
>   Undefined                       first referenced
>    symbol                             in file
>   floor                              
> .libs/ImathColorAlgo.o  (symbol belongs to implicit
> dependency /lib/libm.so.2)
>   sqrtf                               .libs/ImathVec.o
>  (symbol belongs to implicit dependency
> /lib/libm.so.2)
>   ld: fatal: Symbol referencing errors. No output
> written to .libs/libImath.so.4.0.0
>
> Apparently this is caused by the "-zdefs" flag. From
> Sun's docs:
>
>   The link-editor’s -z defs option can be used to
> force a fatal error if any undefined symbols
> remain. This option is recommended when creating any
> shared objects. Shared objects that reference symbols
> from an application can use the -z defs option,
> together with defining the symbols by using an
> extern mapfile directive.
>
> Solaris isn't listed in your supported platforms, but
> maybe it would be easy enough to add a "-lm" to the
> configure?

Are floor() and sqrtf() the only functions that are not defined?
Imath calls sin(), cos(), tan() and several other functions
that are defined in libm.  If libm is missing I would expect
to see more undefined functions.