sprintf() and 64 bit integers

Here's an interesting little thingsthat I came across in CPP Builder 5.  I'm sharing because it caused me considerable grief and maybe I can spare someone else.  (Either that or someone can point to the brain damage that was caused the last time that I had a discussion with my in-laws.)


I've got a multi-threaded application that is a processor emulator.  Standard stuff -- the main thread drives the GUI, the secondary threads are the emulation and related items.  When the emulation ends, processor statistics are dumped.  The counts are all 64 bit unsigned integers (unsigned __int64).

Each line that is written to the dump file is formatted to a static buffer and passed to a synchronized function in the main thread.

Here's a line that doesn't work.  

    sprintf (Message, " 04   %2.2s  %9d EQ,Bi - %9ld true, %9ld false",
      cp_instruction[04].format, Cpu->InstructionCount[04], Cpu->BranchTrueB[0], Cpu->BranchFalseB[0]);

It formats:     04   EQ   41101658 EQ,Bi -         0 true,  40991712 false



However, this code works:

    Len = sprintf (Message, " 04   %2.2s  %9d EQ,Bi - ", cp_instruction[04].format, Cpu->InstructionCount[04]);
    Len += sprintf (Message+Len, "%9ld true, ", Cpu->BranchTrueB[0]);
    Len += sprintf (Message+Len, "%9ld false", Cpu->BranchFalseB[0]);

It formats:     04   EQ   40511708 EQ,Bi -  40401394 true,    110314 false


I've experimented with different integer format specifiers (%d and %ld) but there is no change but the TRUE value is always displayed as 0, with the FALSE value being display and the value that should be displayed for TRUE.

It seems that sprintf () is expecting 32-bit arguments and nothing that I do affects this.  I'll just have to accept that when the count wraps to 33 bits, the value will be really weird.   :)



Kent