Troubles with the stdin in own Windows compiles

[OliverBr]

Maybe someone knows of this issue:

When you open the Windows executable on CMD and then enter “uci” (3-character), the answer won’t show until the next command.
"uci " with space works fine, also "go", "stop", "ponder", "quit" as they have all "even" chars.
This issue has been reported/verified by others on their Windows PC.

I don’t think the problem lies in the code, because the linux/macosx executables work fine.
My own Windows compilations show this strange behaviour.
The problem does not appear with Jim Ablett's Windows compiles.

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	char line[8192];
	while(fgets(line, sizeof(line), stdin)) {

[Roland Chastain]

Weird. I would try this:

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printf("uciok\n");
fflush(stdout); // <---

I will test by myself this afternoon.

P.-S. I have just seen this:

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setbuf(stdout, NULL);

So it probably won't be useful to call fflush.

"uci " with space works fine

Weird.

[Jim Ablett]

I cross-compiled on Linux a Windows executable and it works correctly with no bug.

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CC=clang
CFLAGS=-O3 -Wall -Wextra -mavx2 -mllvm -align-all-nofallthru-blocks=6 -DNDEBUG --target=x86_64-windows-gnu -static
olithink: olithink.c

How are you cross-compiling. On a Mac ?

You could try cleaning up the input. Replace beginning of uci_loop().

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void uci_loop(int d) {
  while (fgets(line, sizeof(line), stdin)) {
    // Remove the newline and carriage return characters
    char *p = strchr(line, '\n');
    if (p) *p = '\0';
    p = strchr(line, '\r');
    if (p) *p = '\0';
    
    // Now perform the comparisons on the cleaned string
    if (strncmp(line, "ucinewgame", 10) == 0) {

Jim.

[benvining]

I believe it is the flushing issue, I experienced this too. In my C++ code I call

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std::cout.flush();

after printing the bestmove. Although now this is making me wonder if I might need to flush in other places too...

[Roland Chastain]

I compiled under Windows (with LLVM-MinGW). I could not reproduce the bug.

Maybe you could try to add this, so that you can see what happens?

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void uci_loop() {
  unsigned long i;
  char hex[256];
  char temp[5];
  while (fgets(line, sizeof(line), stdin)) {
    memset(&hex[0], 0, sizeof(hex));
    for ( i = 0; i < strlen(line); i++ )
    {
      memset(&temp[0], 0, sizeof(temp));
      sprintf(temp, "%0.2X", line[i]);
      strcat(hex, temp);
    }
    printf( "DEBUG line = [0x%s]\n", hex);