add library interface to retrieve memory usage info

  return atoi(lmp->universe->num_ver);

}

/* ---------------------------------------------------------------------- */

/** Get memory usage information

 *

\verbatim embed:rst

This function will retrieve memory usage information for the current

LAMMPS instance or process.  The *meminfo* buffer will be filled with

3 different numbers (if supported by the operating system).  The first

is the tally (in MBytes) of all large memory allocations made by LAMMPS.

This is a lower boundary of how much memory is requested and does not

account for memory allocated on the stack or allocations via ``new``.

The second number is the current memory allocation of the process as

returned by the memory allocator in the C-library.  The third number

is the maximum amount of RAM (not swap) used by the process so far.

If any of the two latter parameters is not supported by the operating

system, the number value is 0.

.. versionadded:: 15Sep2020

\endverbatim

 *

 * \param  handle   pointer to a previously created LAMMPS instance

 * \param  meminfo  buffer with space for at least 3 double to store

 * data in. */

void lammps_memory_usage(void *handle, double *meminfo)

{

  LAMMPS *lmp = (LAMMPS *) handle;

  Info info(lmp);

  info.get_memory_info(meminfo);

}

/* ---------------------------------------------------------------------- */

 * ----------------------------------------------------------------------- */

int    lammps_version(void *handle);

void   lammps_memory_usage(void *handle, double *meminfo);

int    lammps_get_mpi_comm(void *handle);

double lammps_get_natoms(void *handle);

double lammps_get_thermo(void *handle, char *keyword);