C++ APIs

We provide C++ APIs for non-streaming ASR in a single header file.

https://github.com/k2-fsa/sherpa-torch-cpp-makefile-example gives an example of how to use the APIs to decode wave files.

Hint

You can find more examples in https://github.com/k2-fsa/sherpa/tree/master/sherpa/cpp_api

The content of the Makefile from the above repository is given below:

sherpa_install_dir := $(shell python3 -c 'import os; import sherpa; print(os.path.dirname(sherpa.__file__))')
sherpa_cxx_flags := $(shell python3 -c 'import os; import sherpa; print(sherpa.cxx_flags)')

$(info sherpa_install_dir: $(sherpa_install_dir))
$(info sherpa_cxx_flags: $(sherpa_cxx_flags))

CXXFLAGS := -I$(sherpa_install_dir)/include
CXXFLAGS += -Wl,-rpath,$(sherpa_install_dir)/lib
CXXFLAGS += $(sherpa_cxx_flags)
CXXFLAGS += -std=c++14

LDFLAGS := -L $(sherpa_install_dir)/lib -lsherpa_offline_recognizer

$(info CXXFLAGS: $(CXXFLAGS))
$(info LDFLAGS: $(LDFLAGS))

test_decode_files: test_decode_files.cc
  $(CXX) $(CXXFLAGS) -o $@ $< $(LDFLAGS)

.PHONY: clean
clean:
  $(RM) test_decode_files

Basically, you only need to specify the following stuff to use the non-streaming ASR APIs:

• The path to find the header file. You provide:

  CXXFLAGS := -I$(sherpa_install_dir)/include
  

• The library to link to. You provide:

  LDFLAGS := -L $(sherpa_install_dir)/lib -lsherpa_offline_recognizer
  

• The CXX flags used to compile sherpa. You provide:

  CXXFLAGS += $(sherpa_cxx_flags)
  

  Hint

  This one is important. For instance, if sherpa was compiled with -D_GLIBCXX_USE_CXX11_ABI=0 on Linux, you will get link errors like the below one if you don’t use this option in your project.

  test_decode_files.cc:(.text+0x149): undefined reference to
  `sherpa::OfflineRecognizer::OfflineRecognizer(std::__cxx11::basic_string<char,
  std::char_traits<char>, std::allocator<char> > const&, std::__cxx11::basic_string<char,
  std::char_traits<char>, std::allocator<char> > const&, sherpa::DecodingOptions const&, bool, float)'