Winboard Forum

I'm trying to get PSWBTM to work with xboard but I ran into a problem. I don't know how to run executables with spaces for xboard. For Winboard, something like this would work:

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xboard -fd "/home/pradu/Desktop/Buzz" -fcp '"./Buz 2" -log'

But this doesn't work for xboard. Is there any way to launch executables with spaces for xboard?

When you call xboard, you probably use exec() to call it. Arguments in exec() are passed in a structured way, as an array of strings. So it would be obvious to xboard that "./Buzz 2" is a single argument, because it is in a single string.

I don't think that you need to do the actual quoting. That is shell input syntax in Linux, to indicate that the string within the quote is a single argument. But the shell takes that information, strips the quotes off, and passes the stuff within quotes as a single argument to exec.

This might be the problem: that you pass quoted arguments, and that xboard chokes on them,

Sorry, I see now your question is more subtle than that. You have quotes within quotes.

I looked at the xboard code, and the answer is: NOT POSSIBLE. The code in xboard to startup the engine child is very simpleminded: it takes the string passed as -fcp, scans it for spaces, and cuts it at every space into a separate argument. It does not scan for quotes or escapes or anything.

Is this a problem? It is still not too late to try to make it slightly more smart. E.g. delete single quotes, and not cut at speces in between those. But I's rather not., as I cannot test it, and it seems bug-prone. So I'd rather live with the fact that spaces in file names are not allowed. I thought that Linux people would be smart enough to not use such filenames...

OK, if you can compile xboard yourself, you can try to make the following modification in the routine StartChildProcess() in xboard.c:

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    for (;;) {
#if 1
   while(*p == ' ') p++; // skip leading spaces
        if(*p == '"') {
            argv[i++] = ++p;
            p = strchr(p, '"');
   } else if(*p == '\'') {
            argv[i++] = ++p;
            p = strchr(p, '\'');
   } else {
       argv[i++] = p;
       p = strchr(p, ' ');
   }
#else
   argv[i++] = p;
   p = strchr(p, ' ');
#endif
   if (p == NULL) break;
   *p++ = NULLCHAR;
    }


This would treat single and double quoting in the engine command line, and let it protect anything. If you make it #if 0, you have the original code.

I patched this too on SVN.