--- a/gr-fec/include/gnuradio/fec/viterbi.h 2015-12-16 20:39:46
+++ b/gr-fec/include/gnuradio/fec/viterbi.h 2018-08-10 12:33:59
@@ -24,6 +24,13 @@
  * But it fits so nicely into a 32-bit machine word...
  */

+#ifndef INCLUDED_VITERBI_H
+#define INCLUDED_VITERBI_H
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 #include <gnuradio/fec/api.h>

 struct viterbi_state {
@@ -51,3 +58,10 @@

 FEC_API unsigned char
 viterbi_get_output(struct viterbi_state *state, unsigned char *outbuf);
+
+#ifdef __cplusplus
+};
+#endif
+
+#endif /* INCLUDED_VITERBI_H */
+
--- a/gr-fec/lib/viterbi/decode.cc 2015-12-16 20:39:46
+++ b/gr-fec/lib/viterbi/decode.cc 2018-08-10 14:05:31
@@ -49,14 +49,21 @@
   float RATE=0.5;
   float ebn0 = 12.0;
   float esn0 = RATE*pow(10.0, ebn0/10);
+
   gen_met(mettab, amp, esn0, 0.0, 4);

   // Initialize decoder state
   struct viterbi_state state0[64];
   struct viterbi_state state1[64];
   unsigned char viterbi_in[16];
+
   viterbi_chunks_init(state0);

+#ifdef _WIN32
+  setmode (fileno(stdin), O_BINARY);
+  setmode (fileno(stdout), O_BINARY);
+#endif
+
   while (!feof(stdin)) {
     unsigned int n = fread(syms, 1, MAXENCSIZE, stdin);
     unsigned char *out = data;

--- a/gr-fec/lib/viterbi/encode.cc 2015-12-16 20:39:46
+++ b/gr-fec/lib/viterbi/encode.cc 2018-08-10 14:05:55
@@ -44,6 +44,11 @@
   unsigned char data[MAXCHUNKSIZE];
   unsigned char syms[MAXENCSIZE];

+#ifdef _WIN32
+  setmode (fileno(stdin), O_BINARY);
+  setmode (fileno(stdout), O_BINARY);
+#endif
+
   while (!feof(stdin)) {
     unsigned int n = fread(data, 1, MAXCHUNKSIZE, stdin);
     encoder_state = encode(syms, data, n, encoder_state);

--- a/gr-fec/lib/viterbi/metrics.c 2015-12-16 20:39:46
+++ b/gr-fec/lib/viterbi/metrics.c 2018-08-10 09:57:03
@@ -30,6 +30,8 @@
  *
  */

+#include <gnuradio/fec/viterbi.h>
+
 #ifdef HAVE_CONFIG_H
 #include <config.h>
 #endif
@@ -42,8 +44,10 @@
 #include <stdlib.h>
 #include <math.h>

-//declare erf in case it was missing in math.h and provided for by the build system
-extern double erf(double x);
+#ifndef HAVE_ERF
+  //declare erf in case it was missing in math.h and provided for by the build system
+  extern double erf(double x);
+#endif

 /* Normal function integrated from -Inf to x. Range: 0-1 */
 #define	normal(x)	(0.5 + 0.5*erf((x)/M_SQRT2))
@@ -54,7 +58,7 @@
 /* Generate log-likelihood metrics for 8-bit soft quantized channel
  * assuming AWGN and BPSK
  */
-void
+int
 gen_met(int mettab[2][256],	/* Metric table, [sent sym][rx symbol] */
 	int amp,		/* Signal amplitude, units */
 	double esn0,		/* Es/N0 ratio in dB */
@@ -123,4 +127,5 @@
 #endif
     }
   }
+  return (0);
 }