NAME

       rpmem_persist(), rpmem_read(), - functions to copy and read remote pools

SYNOPSIS

              #include <librpmem.h>

              int rpmem_persist(RPMEMpool *rpp, size_t offset,
                  size_t length, unsigned lane);
              int rpmem_deep_persist(RPMEMpool *rpp, size_t offset,
                  size_t length, unsigned lane);
              int rpmem_read(RPMEMpool *rpp, void *buff, size_t offset,
                  size_t length, unsigned lane);

DESCRIPTION

       The  rpmem_persist()  function  copies  data  of  given  length  at  given offset from the
       associated local memory pool and makes sure the data is  persistent  on  the  remote  node
       before  the  function returns.  The remote node is identified by the rpp handle which must
       be returned from either rpmem_open(3) or rpmem_create(3).  The offset is relative  to  the
       pool_addr  specified in the rpmem_open(3) or rpmem_create(3) call.  If the remote pool was
       created using rpmem_create() with non-NULL create_attr argument, offset has to be  greater
       or  equal  to 4096.  In that case the first 4096 bytes of the pool is used for storing the
       pool matadata and cannot be overwritten.  If the pool was created  with  NULL  create_attr
       argument,  the pool metadata is not stored with the pool and offset can be any nonnegative
       number.  The  offset  and  length  combined  must  not  exceed  the  pool_size  passed  to
       rpmem_open(3)  or  rpmem_create(3).   The rpmem_persist() operation is performed using the
       given lane number.  The lane must be less than the  value  returned  by  rpmem_open(3)  or
       rpmem_create(3) through the nlanes argument (so it can take a value from 0 to nlanes - 1).

       The  rpmem_deep_persist() function works in the same way as rpmem_persist(3) function, but
       additionally it flushes the data to the lowest possible persistency domain available  from
       software.  Please see pmem_deep_persist(3) for details.

       The  rpmem_read()  function  reads  length  bytes of data from a remote pool at offset and
       copies it to the buffer buff.  The operation is performed on the specified lane.  The lane
       must  be  less  than  the  value  returned by rpmem_open(3) or rpmem_create(3) through the
       nlanes argument (so it can take a value from 0 to nlanes - 1).  The rpp must  point  to  a
       remote pool opened or created previously by rpmem_open(3) or rpmem_create(3).

RETURN VALUE

       The  rpmem_persist()  function  returns 0 if the entire memory area was made persistent on
       the remote node.  Otherwise it returns a non-zero value and sets errno appropriately.

       The rpmem_read() function returns 0 if the data was read entirely.  Otherwise it returns a
       non-zero value and sets errno appropriately.

SEE ALSO

       rpmem_create(3),     rpmem_open(3),    rpmem_persist(3),    sysconf(3),    limits.conf(5),
       libpmemobj(7) and <http://pmem.io>