new stacktrace function in libpbd3; variable size GUI request thread queues

git-svn-id: svn://localhost/trunk/ardour2@330 d708f5d6-7413-0410-9779-e7cbd77b26cf

libs/pbd3/stacktrace.cc

@@ -0,0 +1,42 @@
+#include <pbd/stacktrace.h>
+#include <iostream>
+
+/* Obtain a backtrace and print it to stdout. */
+
+#ifdef HAVE_EXECINFO
+
+#include <execinfo.h>
+#include <stdlib.h>
+
+void
+PBD::stacktrace (std::ostream& out)
+{
+	void *array[200];
+	size_t size;
+	char **strings;
+	size_t i;
+     
+	size = backtrace (array, 200);
+	strings = backtrace_symbols (array, size);
+     
+	if (strings) {
+
+		printf ("Obtained %zd stack frames.\n", size);
+		
+		for (i = 0; i < size; i++) {
+			out << strings[i] << std::endl;
+		}
+		
+		free (strings);
+	}
+}
+
+#else
+
+void
+PBD::stacktrace (std::ostream& out)
+{
+	out << "stack tracing is not enabled on this platform" << std::endl;
+}
+
+#endif /* HAVE_EXECINFO */