Prevent sending empty line to engine after multi-leg move

As the pmoves are stored internally with a linefeed suffixed to them,
this linefeed was mistaken for a promotion character in the multi-leg
printing formats, and led to an extra empty line being sent to the
engine on non-promotion multi-leg moves. Now a linefeed is replaced
by a null character before sending the move.

diff --git a/backend.c b/backend.c
index 83034f4..23bfda7 100644 (file)
--- a/backend.c
+++ b/backend.c
@@ -5162,14 +5162,14 @@ SendMoveToProgram (int moveNum, ChessProgramState *cps)
       if(moveList[moveNum][4] == ';') { // [HGM] lion: move is double-step over intermediate square
        char *m = moveList[moveNum];
        static char c[2];
-       *c = m[7]; // promoChar
+       *c = m[7]; if(*c == '\n') *c = NULLCHAR; // promoChar
        if((boards[moveNum][m[6]-ONE][m[5]-AAA] < BlackPawn) == (boards[moveNum][m[1]-ONE][m[0]-AAA] < BlackPawn)) // move is kludge to indicate castling
          snprintf(buf, MSG_SIZ, "%c%d%c%d,%c%d%c%d\n", m[0], m[1] - '0', // convert to two moves
                                               m[2], m[3] - '0',
                                               m[5], m[6] - '0',
                                               m[2] + (m[0] > m[5] ? 1 : -1), m[3] - '0');
        else if(*c && m[8]) { // kill square followed by 2 characters: 2nd kill square rather than promo suffix
-         *c = m[9];
+         *c = m[9]; if(*c == '\n') *c = NULLCHAR;
          snprintf(buf, MSG_SIZ, "%c%d%c%d,%c%d%c%d,%c%d%c%d%s\n", m[0], m[1] - '0', // convert to three moves
                                               m[7], m[8] - '0',
                                               m[7], m[8] - '0',