message: Fixing a bug in BP1Base root name
diff: #include "BP1Base.h"
  #include "BP1Base.tcc"
  +#include <iostream>
  +
  +#include "adios2/ADIOSTypes.h" //PathSeparator
  #include "adios2/helper/adiosFunctions.h" //CreateDirectory, StringToTimeUnit
  namespace adios2
  @@ -111,10 +114,15 @@ BP1Base::GetBPNames(const std::vector<std::string> &baseNames) const noexcept
  const int rank) -> std::string {
  const std::string bpBaseName = AddExtension(baseName, ".bp");
  +
  // path/root.bp.dir/root.bp.rank
  - const std::string bpRootName =
  - bpBaseName.substr(bpBaseName.find_last_of(PathSeparator));
  + std::string bpRootName = bpBaseName;
  + const auto lastPathSeparator(bpBaseName.find_last_of(PathSeparator));
  + if (lastPathSeparator != std::string::npos)
  + {
  + bpRootName = bpBaseName.substr(lastPathSeparator);
  + }
  const std::string bpName(bpBaseName + ".dir/" + bpRootName + "." +
  std::to_string(rank));
  return bpName;
  