Hello: I execute make ,then get error: $ make Making all in libsbml/src make[1]: Entering directory `/home/internet/mydoc/test_pj/libsbml/src' ....... /bin/sh ./libtool --tag=CC --mode=link gcc -g -O2 -o test test.o libsbml/src/libsbml.la -lsbml -lstdc++ -lm mkdir .libs gcc -g -O2 -o .libs/test test.o libsbml/src/.libs/libsbml.so -lstdc++ -lm -Wl,--rpath -Wl,/usr/local/lib libsbml/src/.libs/libsbml.so: undefined reference to `safe_strdup' libsbml/src/.libs/libsbml.so: undefined reference to `util_bsearchStringsI' libsbml/src/.libs/libsbml.so: undefined reference to `safe_malloc' libsbml/src/.libs/libsbml.so: undefined reference to `util_PosInf' libsbml/src/.libs/libsbml.so: undefined reference to `util_isInf' libsbml/src/.libs/libsbml.so: undefined reference to `util_NaN' libsbml/src/.libs/libsbml.so: undefined reference to `safe_calloc' libsbml/src/.libs/libsbml.so: undefined reference to `strcmp_insensitive' libsbml/src/.libs/libsbml.so: undefined reference to `c_locale_strtod' Why system can not find these function ,they are system file <stdlib.h> <new> <cmath> which has been included in my app.c. What should I do? Eager to receive your reply! my configure.in file: AC_INIT(main, 0.1, zqiang320@xxxxxxxxx) AM_INIT_AUTOMAKE(foreign) AC_PROG_CC AC_PROG_CXX AM_PROG_LIBTOOL AC_OUTPUT(Makefile libsbml/src/Makefile) my Makefile.am file: bin_PROGRAMS = test SUBDIRS = libsbml/src . test_SOURCES = test.c test_LDADD = libsbml/src/libsbml.la -lsbml -lstdc++ -lm AM_CPPFLAGS = -Ilibsbml/include my libsbml/src/Makefile.am AUTOMAKE_OPTS = gnu lib_LTLIBRARIES = libsbml.la libsbml_la_SOURCES = common/libsbml-version.cpp math/ASTNode.cpp math/FormulaTokenizer.c util/List.cpp AM_CPPFLAGS = -I../include -lsbml -lstdc++ -lm