Standalone C++ example: validate an ONNX model with onnx_light checker#

This page documents examples/check_onnx_light_model, a self-contained CMake project that demonstrates linking with onnx-light and running onnx::checker::check_model() from C++.

Step 1 – Install the C++ library#

From the onnx-light repository root, build and install the static library and its public headers. The Python extension is not required:

cmake -S . -B build-install \
      -DCMAKE_BUILD_TYPE=Release \
      -DONNX_LIGHT_BUILD_PYTHON=OFF \
      -DCMAKE_INSTALL_PREFIX=/usr/local
cmake --build build-install
cmake --install build-install

Step 2 – Build the example#

Point CMAKE_PREFIX_PATH at the install prefix chosen above:

cmake -S examples/check_onnx_light_model -B build-check-onnx-light-model \
      -DCMAKE_BUILD_TYPE=Release \
      -DCMAKE_PREFIX_PATH=/usr/local
cmake --build build-check-onnx-light-model

Step 3 – Run the example#

./build-check-onnx-light-model/check_onnx_light_model path/to/model.onnx 1

The optional full_check argument accepts 0 (default) or 1. When full_check=1, checker runs additional shape-inference validation.

Example output:

Model is valid: path/to/model.onnx
  full_check: true

CMakeLists.txt#

The example uses find_package and links against the exported onnx_light::onnx_light target:

cmake_minimum_required(VERSION 3.15)
project(check_onnx_light_model LANGUAGES CXX)

set(CMAKE_CXX_STANDARD 17)
set(CMAKE_CXX_STANDARD_REQUIRED ON)

find_package(onnx_light REQUIRED)

add_executable(check_onnx_light_model main.cc)
target_link_libraries(check_onnx_light_model PRIVATE onnx_light::onnx_light)

main.cc#

The program calls the path-based checker API and handles validation failures using onnx::checker::ValidationError.

#include "onnx_lib/checker.h"

#include <iostream>

int main(int argc, char *argv[]) {
  if (argc < 2) {
    std::cerr << "Usage: " << argv[0] << " <model.onnx> [full_check]\n";
    return 1;
  }

  try {
    ONNX_LIGHT_NAMESPACE::checker::check_model(argv[1], false);
    std::cout << "Model is valid: " << argv[1] << "\n";
  } catch (const ONNX_LIGHT_NAMESPACE::checker::ValidationError &e) {
    std::cerr << "Validation error:\n" << e.what() << "\n";
    return 2;
  }
  return 0;
}