Description

   The confstr function allows an application to determine the
   current setting of certain system parameters, limits, or options
   that are defined by a string value. The function is mainly used
   by applications to find the system default value for the PATH
   environment variable.

   If the following conditions are true, then the confstr function
   copies that value into a len-byte buffer pointed to by buf:

   o  The len argument can be 0 (zero).

   o  The name argument has a system-defined value.

   o  The buf argument is not a NULL pointer.

   If the returned string is longer than len bytes, including the
   terminating null, then the confstr function truncates the string
   to len - 1 bytes and adds a terminating null to the result. The
   application can detect that the string was truncated by comparing
   the value returned by the confstr function with the value of the
   len argument.

   The <limits.h> header file contains system-defined limits. The
   <unistd.h> header file contains system-defined environmental
   variables.

   Also, confstr supports the following three HP-UX symbolic
   constants, which are added to header file <unistd.h>:

   o  _CS_MACHINE_IDENT

   o  _CS_PARTITION_IDENT

   o  _CS_MACHINE_SERIAL