An idiomatic C++ client library for the Policy Troubleshooter, a service that makes it easier to understand why a user has access to a resource or doesn't have permission to call an API.
While this library is GA, please note Google Cloud C++ client libraries do not follow Semantic Versioning.
Quickstart
The following shows the code that you'll run in the google/cloud/policytroubleshooter/quickstart/ directory, which should give you a taste of the Policy Troubleshooter API C++ client library API.
The library automatically retries requests that fail with transient errors, and uses exponential backoff to backoff between retries. Application developers can override the default policies.
More Information
Error Handling - describes how the library reports errors.
[[["Easy to understand","easyToUnderstand","thumb-up"],["Solved my problem","solvedMyProblem","thumb-up"],["Other","otherUp","thumb-up"]],[["Missing the information I need","missingTheInformationINeed","thumb-down"],["Too complicated / too many steps","tooComplicatedTooManySteps","thumb-down"],["Out of date","outOfDate","thumb-down"],["Samples / code issue","samplesCodeIssue","thumb-down"],["Other","otherDown","thumb-down"]],["Last updated 2025-08-14 UTC."],[[["\u003cp\u003eThe Policy Troubleshooter API C++ Client Library is available to help understand user access to resources and API permissions, and is currently in General Availability (GA).\u003c/p\u003e\n"],["\u003cp\u003eVersion 2.37.0-rc is the latest release candidate, and the library provides access to several versions going back to 2.11.0, along with documentation for each.\u003c/p\u003e\n"],["\u003cp\u003eThe main class, \u003ccode\u003epolicytroubleshooter_v1::IamCheckerClient\u003c/code\u003e, contains the RPCs that can be used to make requests.\u003c/p\u003e\n"],["\u003cp\u003eThe library automatically retries transient errors using exponential backoff, but these policies can be overridden by application developers, and several endpoint and authentication options can be changed.\u003c/p\u003e\n"],["\u003cp\u003eA quickstart is available in the documentation with sample code to begin using the Policy Troubleshooter, demonstrating the library's usage with \u003ccode\u003eIamCheckerClient\u003c/code\u003e.\u003c/p\u003e\n"]]],[],null,["Version 2.11.0keyboard_arrow_down\n\n- [2.42.0-rc (latest)](/cpp/docs/reference/policytroubleshooter/latest)\n- [2.41.0](/cpp/docs/reference/policytroubleshooter/2.41.0)\n- [2.40.0](/cpp/docs/reference/policytroubleshooter/2.40.0)\n- [2.39.0](/cpp/docs/reference/policytroubleshooter/2.39.0)\n- [2.38.0](/cpp/docs/reference/policytroubleshooter/2.38.0)\n- [2.37.0](/cpp/docs/reference/policytroubleshooter/2.37.0)\n- [2.36.0](/cpp/docs/reference/policytroubleshooter/2.36.0)\n- [2.35.0](/cpp/docs/reference/policytroubleshooter/2.35.0)\n- [2.34.0](/cpp/docs/reference/policytroubleshooter/2.34.0)\n- [2.33.0](/cpp/docs/reference/policytroubleshooter/2.33.0)\n- [2.32.0](/cpp/docs/reference/policytroubleshooter/2.32.0)\n- [2.31.0](/cpp/docs/reference/policytroubleshooter/2.31.0)\n- [2.30.0](/cpp/docs/reference/policytroubleshooter/2.30.0)\n- [2.29.0](/cpp/docs/reference/policytroubleshooter/2.29.0)\n- [2.28.0](/cpp/docs/reference/policytroubleshooter/2.28.0)\n- [2.27.0](/cpp/docs/reference/policytroubleshooter/2.27.0)\n- [2.26.0](/cpp/docs/reference/policytroubleshooter/2.26.0)\n- [2.25.1](/cpp/docs/reference/policytroubleshooter/2.25.1)\n- [2.24.0](/cpp/docs/reference/policytroubleshooter/2.24.0)\n- [2.23.0](/cpp/docs/reference/policytroubleshooter/2.23.0)\n- [2.22.1](/cpp/docs/reference/policytroubleshooter/2.22.1)\n- [2.21.0](/cpp/docs/reference/policytroubleshooter/2.21.0)\n- [2.20.0](/cpp/docs/reference/policytroubleshooter/2.20.0)\n- [2.19.0](/cpp/docs/reference/policytroubleshooter/2.19.0)\n- [2.18.0](/cpp/docs/reference/policytroubleshooter/2.18.0)\n- [2.17.0](/cpp/docs/reference/policytroubleshooter/2.17.0)\n- [2.16.0](/cpp/docs/reference/policytroubleshooter/2.16.0)\n- [2.15.1](/cpp/docs/reference/policytroubleshooter/2.15.1)\n- [2.14.0](/cpp/docs/reference/policytroubleshooter/2.14.0)\n- [2.13.0](/cpp/docs/reference/policytroubleshooter/2.13.0)\n- [2.12.0](/cpp/docs/reference/policytroubleshooter/2.12.0)\n- [2.11.0](/cpp/docs/reference/policytroubleshooter/2.11.0) \n\nPolicy Troubleshooter API C++ Client Library\n============================================\n\nAn idiomatic C++ client library for the [Policy Troubleshooter](https://cloud.google.com/iam/docs/troubleshooting-access), a service that makes it easier to understand why a user has access to a resource or doesn't have permission to call an API.\n\nWhile this library is **GA** , please note Google Cloud C++ client libraries do **not** follow [Semantic Versioning](https://semver.org/).\n\n### Quickstart\n\nThe following shows the code that you'll run in the `google/cloud/policytroubleshooter/quickstart/` directory, which should give you a taste of the Policy Troubleshooter API C++ client library API. \n\n #include \"google/cloud/policytroubleshooter/v1/iam_checker_client.h\"\n #include \u003ciostream\u003e\n\n int main(int argc, char* argv[]) try {\n if (argc != 4) {\n std::cerr \u003c\u003c \"Usage: \" \u003c\u003c argv[0] \u003c\u003c \" principal resource-name\"\n \u003c\u003c \" permission\\n\";\n return 1;\n }\n\n namespace policytroubleshooter = ::google::cloud::policytroubleshooter_v1;\n auto client = policytroubleshooter::IamCheckerClient(\n policytroubleshooter::MakeIamCheckerConnection());\n\n google::cloud::policytroubleshooter::v1::TroubleshootIamPolicyRequest request;\n auto& access_tuple = *request.mutable_access_tuple();\n access_tuple.set_principal(argv[1]);\n access_tuple.set_full_resource_name(argv[2]);\n access_tuple.set_permission(argv[3]);\n auto const response = client.TroubleshootIamPolicy(request);\n if (!response) throw std::move(response).status();\n std::cout \u003c\u003c response-\u003eDebugString() \u003c\u003c \"\\n\";\n\n return 0;\n } catch (google::cloud::Status const& status) {\n std::cerr \u003c\u003c \"google::cloud::Status thrown: \" \u003c\u003c status \u003c\u003c \"\\n\";\n return 1;\n }\n\n### Main classes\n\nThe main class in this library is [`policytroubleshooter_v1::IamCheckerClient`](/cpp/docs/reference/policytroubleshooter/2.11.0/classgoogle_1_1cloud_1_1policytroubleshooter__v1_1_1IamCheckerClient). All RPCs are exposed as member functions of this class. Other classes provide helpers, configuration parameters, and infrastructure to mock [`policytroubleshooter_v1::IamCheckerClient`](/cpp/docs/reference/policytroubleshooter/2.11.0/classgoogle_1_1cloud_1_1policytroubleshooter__v1_1_1IamCheckerClient) when testing your application.\n\n### Retry, Backoff, and Idempotency Policies.\n\nThe library automatically retries requests that fail with transient errors, and uses [exponential backoff](https://en.wikipedia.org/wiki/Exponential_backoff) to backoff between retries. Application developers can override the default policies.\n\n### More Information\n\n- [Error Handling](https://cloud.google.com/cpp/docs/reference/common/latest/common-error-handling.html) - describes how the library reports errors.\n- [How to Override the Default Endpoint](/cpp/docs/reference/policytroubleshooter/2.11.0/policytroubleshooter-override-endpoint) - describes how to override the default endpoint.\n- [How to Override the Authentication Credentials](/cpp/docs/reference/policytroubleshooter/2.11.0/policytroubleshooter-override-authentication) - describes how to change the authentication credentials used by the library.\n- [Environment Variables](/cpp/docs/reference/policytroubleshooter/2.11.0/policytroubleshooter-env) - describes environment variables that can configure the behavior of the library."]]