Description

   The fpathconf function allows an application to retrieve the
   characteristics of operations supported by the file system
   underlying the filenamed by the filesdes argument. Read, write,
   or execute permission of the named file is not required, but you
   must be able to search all directories in the path leading to the
   file.

   Symbolic values for the name argument are defined in the
   <unistd.h> header file as follows:

   _PC_LINK_MAX   The maximum number of links to the file. If the
                  filedes argument refers to a directory, the value
                  returned applies to the directory itself.
   _PC_MAX_       The maximum number of bytes in a canonical input
   CANON          line. This is applicable only to terminal devices.
   _PC_MAX_       The number of types allowed in an input queue.
   INPUT          This is applicable only to terminal devices.
   _PC_NAME_MAX   Maximum number of bytes in a filename (not
                  including a terminating null). The byte range
                  value is between 13 and 255. This is applicable
                  only to a directory file. The value returned
                  applies to filenames within the directory.
   _PC_PATH_MAX   Maximum number of bytes in a pathname (not
                  including a terminating null). The value is never
                  larger than 65,535. This is applicable only to a
                  directory file. The value returned is the maximum
                  length of a relative pathname when the specified
                  directory is the working directory.
   _PC_PIPE_BUF   Maximum number of bytes guaranteed to be written
                  atomically. This is applicable only to a FIFO. The
                  value returned applies to the referenced object.
                  If the path argument refers to a directory, the
                  value returned applies to any FIFO that exists or
                  can be created within the directory.
   _PC_CHOWN_     The value returned applies to any files (other
   RESTRICTED     than directories) that exist or can be created
                  within the directory. This is applicable only to a
                  directory file.
   _PC_NO_TRUNC   Returns 1 if supplying a component name longer
                  than allowed by NAME_MAX causes an error. Returns
                  0 (zero) if long component names are truncated.
                  This is applicable only to a directory file.
   _PC_VDISABLE   This is always 0 (zero); no disabling character
                  is defined. This is applicable only to a terminal
                  device.