Added FCPPLIBS variable in makefile to accommodate systems where the fortran...

Added FCPPLIBS variable in makefile to accommodate systems where the fortran compiler needs some extra libraries to link with C++. Also added a Makefile.mac with a possible good library combo.

examples/Makefile

@@ -15,7 +15,7 @@
 # This has had only minimal testing, although it has been known to
 # work. It is likely to work fine for C and C++. For Fortran, you
 # may need to add some of the C/C++ libraries: 
-#    -lc -lm -lstdc++ -lgcc -lgcc_s
+#    -lc -lm -lstdc++ (or -lstdc++.6) -lgcc -lgcc_s
 # but this wasn't required for these examples on Centos 5.2 using
 # gcc 4.1.2.
 
@@ -24,6 +24,11 @@ OpenMM_INSTALL_DIR=/usr/local/openmm
 CFLAGS = -g 
 FFLAGS = -g
 
+# Extra libraries required when gfortran links with a C++ module.
+# Uncomment this on Mac. If this doesn't work, look in /usr/lib to
+# see what versions of libstdc++.so you have and try that.
+# FCPPLIBS = -lstdc++.6
+
 LIB_DIR=$(OpenMM_INSTALL_DIR)/lib
 INCLUDE_DIR=$(OpenMM_INSTALL_DIR)/include
 # assume local directory for C and Fortran wrappers
@@ -55,11 +60,11 @@ HelloSodiumChlorideInC: HelloSodiumChlorideInC.c OpenMM_CWrapper.o
 
 HelloArgonInFortran: HelloArgonInFortran.f90 openmm.mod
 	gfortran $(FFLAGS) HelloArgonInFortran.f90 OpenMM_CWrapper.o \
-	    -L$(LIB_DIR) $(LIBS) -o HelloArgonInFortran
+	    -L$(LIB_DIR) $(LIBS) $(FCPPLIBS) -o HelloArgonInFortran
 
 HelloSodiumChlorideInFortran: HelloSodiumChlorideInFortran.f90 openmm.mod
 	gfortran $(FFLAGS) HelloSodiumChlorideInFortran.f90 OpenMM_CWrapper.o \
-	    -L$(LIB_DIR) $(LIBS) -o HelloSodiumChlorideInFortran
+	    -L$(LIB_DIR) $(LIBS) $(FCPPLIBS) -o HelloSodiumChlorideInFortran
 
 # Build C Wrappers (Fortran depends on this too)
 OpenMM_CWrapper.o: 

examples/Makefile.mac

+## Compiling a Fortran main with C++ can be finicky about libraries.
+## Here FCPPLIBS is set the way we had to do it to work on a Mac.
+## (Otherwise this is just a copy of 'Makefile')
+# ----------------------------------------------------------------------
+# Makefile for OpenMM Preview Release 3 workshop "hello world" examples.
+# June 24, 2009.
+# See https://simtk.org/home/openmm.
+# ----------------------------------------------------------------------
+# This assumes you have gcc compilers for whatever language you are
+# using: g++ for C++ and C, gfortran for Fortran 95.
+# 
+# Note: the C Wrappers and Fortran Module are just prototypes. They are
+# incomplete but have enough functionality to get through these examples.
+# We would like more complete and better-thought-out interfaces; if you
+# have code or ideas please post to the OpenMM forum at the above URL
+# (select "Advanced/Public Forums").
+#
+# This has had only minimal testing, although it has been known to
+# work. It is likely to work fine for C and C++. For Fortran, you
+# may need to add some of the C/C++ libraries: 
+#    -lc -lm -lstdc++ (or -lstdc++.6) -lgcc -lgcc_s
+# but this wasn't required for these examples on Centos 5.2 using
+# gcc 4.1.2.
+
+# Check whether this is the right capitalization for your install directory.
+OpenMM_INSTALL_DIR=/usr/local/openmm
+CFLAGS = -g 
+FFLAGS = -g
+
+# Extra libraries required when gfortran links with a C++ module.
+# Uncomment this on Mac. If this doesn't work, look in /usr/lib to
+# see what versions of libstdc++.so you have and try that.
+FCPPLIBS = -lstdc++.6
+
+LIB_DIR=$(OpenMM_INSTALL_DIR)/lib
+INCLUDE_DIR=$(OpenMM_INSTALL_DIR)/include
+# assume local directory for C and Fortran wrappers
+WRAPPER_DIR=.
+LIBS= -lOpenMM
+
+ALL_CPP_EXAMPLES = HelloArgon HelloSodiumChloride HelloEthane HelloWaterBox
+ALL_C_EXAMPLES   = HelloArgonInC HelloSodiumChlorideInC
+ALL_F95_EXAMPLES = HelloArgonInFortran HelloSodiumChlorideInFortran
+
+ALL_PROGS = $(ALL_CPP_EXAMPLES) $(ALL_C_EXAMPLES) $(ALL_F95_EXAMPLES)
+
+default: HelloArgon
+
+all : $(ALL_PROGS)
+
+# Treat all .cpp source files the same way (except the one that 
+# implements the C Wrappers).
+.cpp : 
+	g++ $(CFLAGS) $< -I$(INCLUDE_DIR) -L$(LIB_DIR) $(LIBS) -o $*
+
+HelloArgonInC: HelloArgonInC.c OpenMM_CWrapper.o
+	g++ $(CFLAGS) -I$(WRAPPER_DIR) HelloArgonInC.c OpenMM_CWrapper.o \
+        -L$(LIB_DIR) $(LIBS) -o HelloArgonInC
+
+HelloSodiumChlorideInC: HelloSodiumChlorideInC.c OpenMM_CWrapper.o
+	g++ $(CFLAGS) -I$(WRAPPER_DIR) HelloSodiumChlorideInC.c OpenMM_CWrapper.o \
+        -L$(LIB_DIR) $(LIBS) -o HelloSodiumChlorideInC
+
+HelloArgonInFortran: HelloArgonInFortran.f90 openmm.mod
+	gfortran $(FFLAGS) HelloArgonInFortran.f90 OpenMM_CWrapper.o \
+	    -L$(LIB_DIR) $(LIBS) $(FCPPLIBS) -o HelloArgonInFortran
+
+HelloSodiumChlorideInFortran: HelloSodiumChlorideInFortran.f90 openmm.mod
+	gfortran $(FFLAGS) HelloSodiumChlorideInFortran.f90 OpenMM_CWrapper.o \
+	    -L$(LIB_DIR) $(LIBS) $(FCPPLIBS) -o HelloSodiumChlorideInFortran
+
+# Build C Wrappers (Fortran depends on this too)
+OpenMM_CWrapper.o: 
+	g++ -c $(CFLAGS) -I$(WRAPPER_DIR) -I$(INCLUDE_DIR) \
+         $(WRAPPER_DIR)/OpenMM_CWrapper.cpp -o OpenMM_CWrapper.o
+
+# Build Fortran 95 Module file
+openmm.mod:
+	gfortran -c $(FFLAGS) $(WRAPPER_DIR)/OpenMM_Module.f90
+
+clean : 
+	rm $(ALL_PROGS) *.o *.mod
+

examples/MakefileNotes.txt

@@ -5,7 +5,7 @@ You must already have the OpenMM binaries installed from SimTK.org/home/OpenMM.
 instructions -- if you are hoping to get GPU acceleration you 
 may also have to install appropriate vendor libraries and a driver.
 
-You may need to slightly edit the Makefile to make it run on your system, depending where you installed OpenMM.
+You may need to slightly edit the Makefile to make it run on your system, depending where you installed OpenMM and the particular requirements of your version of gcc for mixed Fortran/C++ programming. There is a copy of the Makefile called 'Makefile.mac' which uses a library that worked for us on Mac.
 
 Type "make" (or "make default") to get just one C++ example built
 (HelloArgon). Make sure it runs.