Changed code to use C++ functions, and select Panging Requests starting from message type byte - the effect will be probably shorter and easier to read code.
diff --git a/lib/misc_utils/tmsi_dumper_impl.h b/lib/misc_utils/tmsi_dumper_impl.h
index 759ccac..8b5a038 100644
--- a/lib/misc_utils/tmsi_dumper_impl.h
+++ b/lib/misc_utils/tmsi_dumper_impl.h
@@ -24,6 +24,8 @@
 #define INCLUDED_GSM_TMSI_DUMPER_IMPL_H
 
 #include <grgsm/misc_utils/tmsi_dumper.h>
+#include <fstream>
+#include <ctime>
 
 namespace gr {
   namespace gsm {
@@ -31,8 +33,11 @@
     class tmsi_dumper_impl : public tmsi_dumper
     {
      private:
+      std::ofstream dump_file;
       void dump_tmsi(pmt::pmt_t msg);
-
+      void write_timestamp(tm * now);
+      void write_imsi(uint8_t * imsi);
+      void write_tmsi(uint8_t * tmsi);
      public:
       tmsi_dumper_impl();
       ~tmsi_dumper_impl();