Moderator: Ras
Hi Folkert,
Well, usually I don't RTFMAlexander Schmidt wrote: ↑Sat Apr 04, 2026 7:42 am RTFM
You need to start the engine with the command line argument "-xboard".
- when I saw that it supports the WB protocol, I assumed that the usual 'xboard' command (sent by Arena) would be enough to put it into xboard mode.
Yep, now it's working without problems!Jim Ablett wrote: ↑Sat Apr 04, 2026 12:32 am Winboard fixed time per move tc wasn't working. Fixed now.
The same happened to me, I already opened talkchess for a complaint before I remembered to RTFMF.Huber wrote: ↑Sat Apr 04, 2026 1:04 pmWell, usually I don't RTFMAlexander Schmidt wrote: ↑Sat Apr 04, 2026 7:42 am RTFM
You need to start the engine with the command line argument "-xboard".
Seems this version can't run on the Fritz 20 GUI. Haven't tried the first version yet. UPDATE: Engine from first post is actually the same as the updated engine so I'm guessing you updated the links on the first post.Jim Ablett wrote: ↑Fri Apr 03, 2026 8:15 pm Small update: enable engine to use gui opening books
Proton link:
https://drive.proton.me/urls/SYXDFSN22W#s412WevZRDVY
Smash link:
https://fromsmash.com/PDP11CHESS6JA64
Jim.
Engine only supports winboard protocol. Should work with wb2uci to get it working with Chessbase but I haven't tested it. Proton link doesn't change, just gets updated.Leto wrote: ↑Sat Apr 04, 2026 4:35 pmSeems this version can't run on the Fritz 20 GUI. Haven't tried the first version yet. UPDATE: Engine from first post is actually the same as the updated engine so I'm guessing you updated the links on the first post.Jim Ablett wrote: ↑Fri Apr 03, 2026 8:15 pm Small update: enable engine to use gui opening books
Proton link:
https://drive.proton.me/urls/SYXDFSN22W#s412WevZRDVY
Smash link:
https://fromsmash.com/PDP11CHESS6JA64
Jim.
Code: Select all
io.c:21:13: error: too many arguments provided to function-like macro invocation
21 | int getchar(void) {
| ^
/usr/include/stdio.h:512:9: note: macro 'getchar' defined here
512 | #define getchar() getc(stdin)
| ^
io.c:21:5: error: redefinition of 'getchar' as different kind of symbol
21 | int getchar(void) {
| ^
/usr/include/stdio.h:286:6: note: previous definition is here
286 | int getchar(void);
| ^
io.c:21:12: error: expected ';' after top level declarator
21 | int getchar(void) {
| ^
| ;
Hi Christian, just #undef itcpeters wrote: ↑Sat Apr 04, 2026 10:20 pm Hey Jim,
while it does compile on linux and computes there, on newer *BSDs the compiler stumples:
Happy Easter!Code: Select all
io.c:21:13: error: too many arguments provided to function-like macro invocation 21 | int getchar(void) { | ^ /usr/include/stdio.h:512:9: note: macro 'getchar' defined here 512 | #define getchar() getc(stdin) | ^ io.c:21:5: error: redefinition of 'getchar' as different kind of symbol 21 | int getchar(void) { | ^ /usr/include/stdio.h:286:6: note: previous definition is here 286 | int getchar(void); | ^ io.c:21:12: error: expected ';' after top level declarator 21 | int getchar(void) { | ^ | ;
Code: Select all
#include <stdio.h>
#undef getchar
int getchar(void) {
Code: Select all
cp@bsd15: ~/schach/chess_6
$ ./chess [23:34:47]
PDP-11 Chess Engine
Search depth: 8
Opening book: ON
Book file: book.dat (274 bytes)
Opening book loaded successfully
usermove e2e4
eh?
exit
cp@bsd15: ~/schach/chess_6
$ ./chess -xboard [23:35:19]
BOOK: book.dat size=274 bytes
usermove e2e4
move g8f6
usermove e4e5Hi Christian,cpeters wrote: ↑Sun Apr 05, 2026 11:55 pm Hello Jim,
this solves the problem of compilation, but belle cannot give a move after out of book:
After this move it's occupied (computes 100% forever) but doesn't answer. And do I understand it correctly: The programm will not work in console (to a certain point: I can set options and show the board but beyond that...) as such/without speaking xboard-lingo with it (at least that's what I experienced under linux)?Code: Select all
cp@bsd15: ~/schach/chess_6 $ ./chess [23:34:47] PDP-11 Chess Engine Search depth: 8 Opening book: ON Book file: book.dat (274 bytes) Opening book loaded successfully usermove e2e4 eh? exit cp@bsd15: ~/schach/chess_6 $ ./chess -xboard [23:35:19] BOOK: book.dat size=274 bytes usermove e2e4 move g8f6 usermove e4e5
Greetings
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Chess Engine User Commands
Game Control Commands
---------------------
Command Description
save Saves the current game state to a file named "chess.out"
restore Restores a previously saved game from "chess.out"
exit Exits the chess program
resign Resigns the current game (calls handle_hup)
Move Input Commands
-------------------
Command Description
[empty line] Pressing Enter with no input displays the current board position
Algebraic notation (e.g., e2e4) Enters a move in algebraic format (enabled with mfmt on)
Descriptive notation (e.g., P/K4) Enters a move in descriptive format (default when mfmt off)
Display Commands
----------------
Command Description
mfmt Toggles algebraic notation on/off
mfmt on Enables algebraic notation (e.g., "e2e4")
mfmt off Disables algebraic notation (uses descriptive format)
score Displays the current evaluation score for both sides
clock Shows the accumulated thinking time for both players
hint Calculates and displays the best move and its evaluation
repeat Replays all moves made so far in the game
Game Analysis Commands
----------------------
Command Description
test Toggles test mode (shows heuristic evaluations during search)
setup Enters board setup mode for custom positions
remove Takes back the last two moves (useful for analyzing alternatives)
first Sets the engine to play first (White) - only valid at start of game
manual Toggles manual mode (human plays both sides)
Time Control Commands
---------------------
Command Description
time Toggles time control on/off or shows current setting
time <seconds> Sets the engine to think for specified seconds per move (e.g., time 10)
Opening Book Commands
---------------------
Command Description
book Toggles opening book on/off
book on Enables opening book
book off Disables opening book
Special Commands
----------------
Command Description
o-o or oo Castles kingside in descriptive notation
o-o-o or ooo Castles queenside in descriptive notation
alg Alias for mfmt on (only valid at game start)
Xboard Commands
----------------
Command Description
-xboard Use xboard protocol
-nobook Disable opening book use
Command Examples
----------------
./Chess
mfmt on # Enable algebraic notation
time 10 # Set 10 seconds thinking time
book off # Disable opening book
e2e4 # Play e4 as White
# After Black plays, get a hint
hint # Shows best move and evaluation
# Check thinking time
clock # Shows time used by each player
# Take back a move to try something else
remove # Takes back last two moves
# Save the game for later
save # Saves to chess.out
# Exit the program
exit
Default Settings
• Algebraic notation: OFF (uses descriptive format)
• Opening book: ON
• Time control: OFF (uses fixed depth search)
• Manual mode: OFF (engine plays)
• Test mode: OFF
• Default depth: 8 ply
Notes
• Commands are case-sensitive and must be entered in lowercase
• Pressing Enter with no input shows the current board position
• The first command only works at the start of a game
• The remove command removes two moves (one full turn) to return to a previous position
• When time control is enabled, the engine ignores the fixed depth setting and searches until time runs out