Use a convenience library

Makefile.am

@@ -2,10 +2,19 @@ include $(top_srcdir)/build-aux/glib-tap.mk
 
 AM_CFLAGS = # CFLAGS applicable to all executables (products)
 
+# Convenience library so that it can be resued 
+# between my_executable and the tests
+noinst_LIBRARIES = libcommon.a
+libcommon_a_SOURCES = src/common.c
+
+# The main product 
 bin_PROGRAMS = myexecutable # make all will generate ./my_executable 
 myexecutable_SOURCES = \
                        src/main.c
 myexecutable_CFLAGS = #--std=c11 # CFLAGS applicable to myexecutable_SOURCES
+myexecutable_LDADD = libcommon.a
+
+
 
 # Tests
 # 'check' comes from 'make check'
@@ -19,7 +28,8 @@ testsuite_SOURCES = tests/test.c
 # CFLAGS and -l options that are retrieved from pkg-config (configure.ac)
 # DEPS_CFLAGS and DEPS_LIBS are filled by PKG_CHECK_MODULES (configure.ac)
 
+testsuite_CPPFLAGS = -I$(top_srcdir)/src
 testsuite_CFLAGS = $(GLIB_CFLAGS) # DEPS_* are filled by PKG_CHECK_MODULES 
-testsuite_LDADD = $(GLIB_LIBS)     # in configure.ac
+testsuite_LDADD = $(GLIB_LIBS) libcommon.a    # in configure.ac
 
 

configure.ac

@@ -30,6 +30,8 @@ AC_PROG_CC
 AC_PROG_CC_C99 # or AC_PROG_CC_89 to force C89 mode or AC_PROG_CC_STDC to go to latest supported standard (currently C99)
 
 AC_PROG_INSTALL
+AC_PROG_CC_C_O # Need to have per product flags myexecutable_CFLAG
+AC_PROG_RANLIB # Need for to create libraries: .a 
 
 # Checks for libraries.
 

src/common.c

@@ -0,0 +1,6 @@
+#include <stdio.h>
+#include "common.h"
+void myfunc()
+{
+  printf("myfunc() called\n");
+}

src/common.h

@@ -0,0 +1,5 @@
+#ifndef COMMON_H
+#define COMMON_H
+void myfunc();
+
+#endif /* COMMON_H */

src/main.c

@@ -1,7 +1,9 @@
 #include <stdio.h>
+#include "common.h"
 
 int main(int argc, char *argv[])
 {
   printf ("Hello world\n");
+  myfunc();
   return 0;
 }

tests/test.c

@@ -3,6 +3,8 @@
 #include <stdlib.h>
 #include <stdbool.h>
 
+#include "common.h"
+
 typedef struct {
   int a; /* usually some other data structure that you
           * need for your tests */
@@ -26,6 +28,7 @@ void my_second_test(dfixture *df, gconstpointer ignored) {
 }
 
 void my_third_test(dfixture *df, gconstpointer ignored) {
+  myfunc();
   g_test_incomplete("incomplete means that there is some functionality missing");
 }