apr  1.7.0
About: APR (Apache Portable Runtime) project offers software libraries that provide a predictable and consistent interface to underlying platform-specific implementations (APR core library).
  Fossies Dox: apr-1.7.0.tar.bz2  ("inofficial" and yet experimental doxygen-generated source code documentation)  

APR Error Space
Collaboration diagram for APR Error Space:
The following attempts to show the relation of the various constants
used for mapping APR Status codes.
      0
 20,000     APR_OS_START_ERROR
        + APR_OS_ERRSPACE_SIZE (50,000)
 70,000      APR_OS_START_STATUS
        + APR_OS_ERRSPACE_SIZE - APR_UTIL_ERRSPACE_SIZE (30,000)
100,000      APR_UTIL_START_STATUS
        + APR_UTIL_ERRSPACE_SIZE (20,000)
120,000      APR_OS_START_USERERR
        + 10 x APR_OS_ERRSPACE_SIZE (50,000 * 10)
620,000      APR_OS_START_CANONERR
        + APR_OS_ERRSPACE_SIZE (50,000)
670,000      APR_OS_START_EAIERR
        + APR_OS_ERRSPACE_SIZE (50,000)
720,000      APR_OS_START_SYSERR