diff --git a/src/fit.cc b/src/fit.cc
index e2a5afa9..f12f21fe 100644
--- a/src/fit.cc
+++ b/src/fit.cc
@@ -49,34 +49,38 @@ read_number_sequence(istream &in, numseq_t &numseq) {
 
 const std::string VERSION_STRING = (std::string)PACKAGE_STRING;
 
-bool help;
-bool version;
-bool verbose;
+struct fit_clp {
+    bool help;
+    bool version;
+    bool verbose;
 
-string filename; // file that contains the sequence of numbers
+    string filename; // file that contains the sequence of numbers
 
-double delta_ab; // penalty for a change a->b
-double delta_ba; // penalty for a change b->a
+    double delta_ab; // penalty for a change a->b
+    double delta_ba; // penalty for a change b->a
 
-double beta = 12; // inverse temperature
+    double beta = 12; // inverse temperature
 
-bool opt_once_on;
+    bool opt_once_on;
 
-bool opt_all_values;
+    bool opt_all_values;
+};
+
+fit_clp clp;
 
 option_def my_options[] =
-    {{"help", 'h', &help, O_NO_ARG, 0, O_NODEFAULT, "", "This help"},
-     {"version", 'V', &version, O_NO_ARG, 0, O_NODEFAULT, "", "Version info"},
-     {"verbose", 'v', &verbose, O_NO_ARG, 0, O_NODEFAULT, "", "Verbose"},
+    {{"help", 'h', &clp.help, O_NO_ARG, 0, O_NODEFAULT, "", "This help"},
+     {"version", 'V', &clp.version, O_NO_ARG, 0, O_NODEFAULT, "", "Version info"},
+     {"verbose", 'v', &clp.verbose, O_NO_ARG, 0, O_NODEFAULT, "", "Verbose"},
 
-     {"delta", 'd', 0, O_ARG_DOUBLE, &delta_ab, "0.5", "float",
+     {"delta", 'd', 0, O_ARG_DOUBLE, &clp.delta_ab, "0.5", "float",
       "Penalty for state change"},
-     {"beta", 'b', 0, O_ARG_DOUBLE, &beta, "6", "float", "Inverse temperature"},
-     {"once-on", 0, &opt_once_on, O_NO_ARG, 0, O_NODEFAULT, "",
+     {"beta", 'b', 0, O_ARG_DOUBLE, &clp.beta, "6", "float", "Inverse temperature"},
+     {"once-on", 0, &clp.opt_once_on, O_NO_ARG, 0, O_NODEFAULT, "",
       "Fit a signal that is on only once"},
-     {"all-values", 0, &opt_all_values, O_NO_ARG, 0, O_NODEFAULT, "",
+     {"all-values", 0, &clp.opt_all_values, O_NO_ARG, 0, O_NODEFAULT, "",
       "Show all function values of signal (instead of only ranges)"},
-     {"", 0, 0, O_ARG_STRING, &filename, "profile.dat", "file",
+     {"", 0, 0, O_ARG_STRING, &clp.filename, "profile.dat", "file",
       "Input file with sequence of numbers"},
      {"", 0, 0, 0, 0, O_NODEFAULT, "", ""}};
 
@@ -85,7 +89,7 @@ option_def my_options[] =
 
 int
 main(int argc, char **argv) {
-    delta_ba = delta_ab; // always use same penalties for a->b and b->a
+    clp.delta_ba = clp.delta_ab; // always use same penalties for a->b and b->a
 
     double c0 = 0.2;
     double c1 = 0.6; // initial on off values
@@ -95,7 +99,7 @@ main(int argc, char **argv) {
     //
     bool process_success = process_options(argc, argv, my_options);
 
-    if (help) {
+    if (clp.help) {
         cout << "locarnap_fit - Fit a two step function to a data series."
              << endl
              << endl;
@@ -107,9 +111,9 @@ main(int argc, char **argv) {
         return 0;
     }
 
-    if (version || verbose) {
+    if (clp.version || clp.verbose) {
         cout << "locarnap_fit (" << VERSION_STRING << ")" << endl;
-        if (version)
+        if (clp.version)
             return 0;
         else
             cout << endl;
@@ -121,7 +125,7 @@ main(int argc, char **argv) {
         return -1;
     }
 
-    if (verbose) {
+    if (clp.verbose) {
         print_options(my_options);
     }
     //
@@ -133,16 +137,16 @@ main(int argc, char **argv) {
     //
     numseq_t numseq;
 
-    if (filename == "-") {
+    if (clp.filename == "-") {
         read_number_sequence(std::cin, numseq);
     } else {
-        read_number_sequence(filename, numseq);
+        read_number_sequence(clp.filename, numseq);
     }
 
     // ----------------------------------------
     // optimize on/off-values and compute fit
     //
-    FitOnOff fns(numseq, delta_ab, delta_ba, beta);
+    FitOnOff fns(numseq, clp.delta_ab, clp.delta_ba, clp.beta);
 
     // double viterbi_score;
 
@@ -151,7 +155,7 @@ main(int argc, char **argv) {
     c0 = opt.first;
     c1 = opt.second;
 
-    if (opt_once_on) {
+    if (clp.opt_once_on) {
         // run once on optimization
         double on = std::max(c0, c1);
         double off = std::min(c0, c1);
@@ -169,8 +173,8 @@ main(int argc, char **argv) {
     // write best fit
     //
 
-    if (!opt_all_values) {
-        if (opt_once_on)
+    if (!clp.opt_all_values) {
+        if (clp.opt_once_on)
             cout << "ONOFF " << min(c0, c1) << " " << max(c0, c1) << endl;
         else
             cout << "ONOFF " << c0 << " " << c1 << endl;