Re: [TUHS] PDP-8

In message: <20101002210346.GE27937(a)bitmover.com> Larry McVoy <lm(a)bitmover.com> writes: : > > If you could look at the stack frames and give me a stack trace : > > that's more or less the same thing. : > : > (gdb) bt : > : > The real question is not to get a stack trace, but to analyse it. : : Hmm, we seem to have a different view. I like people who can write : the gdb bt code, not run it. This isn't an imaginary thing, one of : my guys showed up one day with his own hand rolled backtrace that we : ended up putting in our product for support. : : The advantage of his, over the following hack we had before, was that : it worked when no gdb was installed (windows): : : void : gdb_backtrace(void) : { : FILE *f; : char *cmd; : : unless (getenv("_BK_BACKTRACE")) return; : unless ((f = efopen("BK_TTYPRINTF")) || : (f = fopen(DEV_TTY, "w"))) { : f = stderr; : } : cmd = aprintf("gdb -batch -ex backtrace '%s/bk' %u 1>&%d 2>&%d", : bin, getpid(), fileno(f), fileno(f)); : : system(cmd); : free(cmd); : if (f != stderr) fclose(f); : } Stack back traces are easy on x86, but get a lot harder on !x86 at high optimization layers without help from libunwind. That's the down side of not relying on gdb... :) Warner