Function StringPrintf

BeefRT/gperftools/src/tests/sampler_test.cc:86–93

#define LOG(level)  std::cerr << "\n"

static std::string StringPrintf(const char* format, ...) {
  char buf[256];   // should be big enough for all logging
  va_list ap;
  va_start(ap, format);
  perftools_vsnprintf(buf, sizeof(buf), format, ap);
  va_end(ap);
  return buf;
}

namespace {
template<typename T> class scoped_array {