add example to COUPLE folder demonstrating loading LAMMPS as a plugin.

examples/COUPLE/plugin/liblammpsplugin.c

@@ -0,0 +1,99 @@
+/* -*- c++ -*- ----------------------------------------------------------
+   LAMMPS - Large-scale Atomic/Molecular Massively Parallel Simulator
+   http://lammps.sandia.gov, Sandia National Laboratories
+   Steve Plimpton, sjplimp@sandia.gov
+
+   Copyright (2003) Sandia Corporation.  Under the terms of Contract
+   DE-AC04-94AL85000 with Sandia Corporation, the U.S. Government retains
+   certain rights in this software.  This software is distributed under
+   the GNU General Public License.
+
+   See the README file in the top-level LAMMPS directory.
+------------------------------------------------------------------------- */
+
+/*
+   Variant of the C style library interface to LAMMPS
+   that uses a shared library and dynamically opens it,
+   so this can be used as a prototype code to integrate
+   a LAMMPS plugin to some other software.
+*/
+
+#include "library.h"
+#include "liblammpsplugin.h"
+#include <stdlib.h>
+#include <dlfcn.h>
+
+liblammpsplugin_t *liblammpsplugin_load(const char *lib)
+{
+  liblammpsplugin_t *lmp;
+  void *handle;
+
+  if (lib == NULL) return NULL;
+  handle = dlopen(lib,RTLD_NOW|RTLD_GLOBAL);
+  if (handle == NULL) return NULL;
+  
+  lmp = (liblammpsplugin_t *) malloc(sizeof(liblammpsplugin_t));
+  lmp->handle = handle;
+
+#define ADDSYM(symbol) lmp->symbol = dlsym(handle,"lammps_" #symbol)
+  ADDSYM(open);
+  ADDSYM(open_no_mpi);
+  ADDSYM(close);
+  ADDSYM(version);
+  ADDSYM(file);
+  ADDSYM(command);
+  ADDSYM(commands_list);
+  ADDSYM(commands_string);
+  ADDSYM(free);
+  ADDSYM(extract_setting);
+  ADDSYM(extract_global);
+  ADDSYM(extract_box);
+  ADDSYM(extract_atom);
+  ADDSYM(extract_compute);
+  ADDSYM(extract_fix);
+  ADDSYM(extract_variable);
+
+  ADDSYM(get_thermo);
+  ADDSYM(get_natoms);
+
+  ADDSYM(set_variable);
+  ADDSYM(reset_box);
+
+  ADDSYM(gather_atoms);
+  ADDSYM(gather_atoms_concat);
+  ADDSYM(gather_atoms_subset);
+  ADDSYM(scatter_atoms);
+  ADDSYM(scatter_atoms_subset);
+
+  ADDSYM(set_fix_external_callback);
+
+  ADDSYM(config_has_package);
+  ADDSYM(config_package_count);
+  ADDSYM(config_package_name);
+  ADDSYM(config_has_gzip_support);
+  ADDSYM(config_has_png_support);
+  ADDSYM(config_has_jpeg_support);
+  ADDSYM(config_has_ffmpeg_support);
+  ADDSYM(config_has_exceptions);
+  ADDSYM(create_atoms);
+#ifdef LAMMPS_EXCEPTIONS
+  lmp->has_exceptions = 1;
+  ADDSYM(has_error);
+  ADDSYM(get_last_error_message);
+#else
+  lmp->has_exceptions = 0;
+  lmp->has_error = NULL;
+  lmp->get_last_error_message = NULL;
+#endif
+  return lmp;
+}
+
+int liblammpsplugin_release(liblammpsplugin_t *lmp)
+{
+  if (lmp == NULL) return 1;
+  if (lmp->handle == NULL) return 2;
+
+  dlclose(lmp->handle);
+  free((void *)lmp);
+  return 0;
+}