[gdal-dev] cpl_port.h CPL_LSB macro setting

[Frank Warmerdam]

Rubin, Jared wrote:
> 
> Is there a test in configure script to set the CPL_LSB macro automatically?
> I am building on both big and little endian and I am not seeing the 
> macro being set
> CPL_IS_LSB is not being set to either 0 or 1
> thanks

Jared,

The AC_C_BIGENDIAN step in configure sets the WORDS_BIGENDIAN macro (or not)
in cpl_config.h.  cpl_port.h then checks for this to decide whether to set
CPL_LSB or CPL_MSB and how to set CPL_IS_LSB.

The following code in cpl_port.h should ensure that anything including
cpl_port.h gets a 1 or 0 definition of CPL_IS_LSB.  Note that there are
some files (such as sublibraries such as libtiff or libpng) that do not
include cpl_port.h.

#if defined(CPL_LSB)
#  define CPL_IS_LSB 1
#else
#  define CPL_IS_LSB 0
#endif

Best regards,
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