Byte order signatures are known integer values that are available in the foreign system's byte oder. By examining these on a byte by byte basis, the byte ordering of the remote system can be determined. While typically systems have a consistent ordering of bytes in words and words in longwords, the library does not assume that.
A system that is supplying data to be converted with this library must provide a 16 bit and a 32 bit signature. These are the values 0x0102 and 0x01020304 repsectively written in that system's native byte ordering.
The function makecvtblock takes those signatures
and delivers a DaqConversion block. The
DaqConversion block is a data structure that provides
conversion tables for foreign to host and host to foreign conversions.
Suppose you have data in a structure that contains these signatures
as fields named s_ssig and
s_lsig. The example below shows how to
create a conversion block:
Example 37-4. Creating a DaqConversion
#include <cvt.h>
...
DaqConversion conversionBlock;
makecvtblock(data.s_lsig, data.s_ssig, &conversionBlock);
...
The DaqConversion block
conversionBlock
can be used in subsequent calls to do byte order conversions.