diff --git a/src/msspec/spec/fortran/SConstruct b/src/msspec/spec/fortran/SConstruct
index dc1ef60..5791198 100644
--- a/src/msspec/spec/fortran/SConstruct
+++ b/src/msspec/spec/fortran/SConstruct
@@ -1,8 +1,44 @@
 from sysconfig import get_config_var
 import os
 
+SetOption('silent', True)
+# Define the command line options
+AddOption('--dbg',
+          dest='dbg',
+          action='store_true',
+          help='add debugging symbols')
+
+AddOption('--verbose',
+          dest='verbose',
+          action='store_true',
+          help='add debugging symbols')
+
+
+# define environments
 COMP_OPTS = ['-O2', '-ffast-math', '-fno-automatic']
-env = Environment(tools=['default', 'gfortran'], FORTRAN='gfortran', FORTRANFLAGS=" ".join(['-fPIC'] + COMP_OPTS))
+#std = Environment(tools=['default', 'gfortran'], FORTRAN='gfortran', 
+std = Environment(FORTRAN='gfortran', 
+		              FORTRANFLAGS=['-fPIC', '-O2', '-ffast-math', '-fno-automatic'],
+		              F2PY_OPTS=[],
+									FORTRANCOMSTR = "building $TARGET ...")
+
+dbg = std.Clone()
+dbg.Append(FORTRANFLAGS = ['-g', '-Wall', '-Wextra', '-Warray-temporaries', '-Wconversion', '-fbacktrace', 
+					                 '-ffree-line-length-0', '-fcheck=all', '-ffpe-trap=zero,overflow,underflow',
+												   '-finit-real=nan'])
+dbg.Append(F2PY_OPTS = ['--debug-capi', '--debug'])
+
+env = std
+if GetOption('dbg'):
+	env = dbg
+
+if GetOption('verbose'):
+	SetOption('silent', False)
+	#env.Replace(FORTRANCOMSTR = "")
+
+
+
+suffix = get_config_var('EXT_SUFFIX')
 
 sources = {
 	'dim_mod_src'               : ['memalloc/dim_mod.f'],
@@ -10,21 +46,19 @@ sources = {
 	'cluster_gen_src'           : Glob('cluster_gen/*.f'),
 	'common_sub_src'            : Glob('common_sub/*.f'),
 	'renormalization_src'       : Glob('renormalization/*.f'),
-        'phd_se_noso_nosp_nosym_src': Glob('phd_se_noso_nosp_nosym/*.f'),
-        'phd_mi_noso_nosp_nosym_src': Glob('phd_mi_noso_nosp_nosym/*.f'),
-        'eig_common_src'            : Glob('eig/common/*.f'),
-        'eig_mi_src'                : Glob('eig/mi/*.f'),
-        'eig_pw_src'                : Glob('eig/pw/*.f')}
+  'phd_se_noso_nosp_nosym_src': Glob('phd_se_noso_nosp_nosym/*.f'),
+  'phd_mi_noso_nosp_nosym_src': Glob('phd_mi_noso_nosp_nosym/*.f'),
+  'eig_common_src'            : Glob('eig/common/*.f'),
+  'eig_mi_src'                : Glob('eig/mi/*.f'),
+  'eig_pw_src'                : Glob('eig/pw/*.f')}
 
 objects = {}
 for k, v in sources.items():
-	objects[k.replace('_src', '_obj')] = env.Object(sources[k])
+	objects[k.replace('_src', '_obj')] = env.Object(v)
 	
 Requires(objects['memalloc_obj'], objects['dim_mod_obj'])
 
 
-suffix = get_config_var('EXT_SUFFIX')
-cmd = "f2py3 -I. " + " ".join([str(_) for _ in objects if str(_).endswith('.o')]) + f" -c -m $MODULENAME $SOURCE"
 
 shared_objects = {
 	'phd_se_noso_nosp_nosym': 'phd_se_noso_nosp_nosym/main.f',
@@ -34,7 +68,9 @@ shared_objects = {
 modules = {}
 
 for k, v in shared_objects.items():
-	env['MODULENAME'] = k
-	modules[k] = env.Command(k + suffix, v, cmd)
-	Requires(modules[k], objects.values())
+	cmd = "f2py3 -I. " + " ".join([str(_) for _ in objects if str(_).endswith('.o')]) + f"$F2PY_OPTS -c -m {k} $SOURCE"
+	cmd += " 1>/dev/null"
+	modules[k + suffix] = env.Command(k + suffix, v, Action(cmd, 'Building Python module $TARGET'))
+	Requires(modules[k + suffix], objects.values())
+