A number of environment variables can be used to configure the behavior of the library. There are also functions to configure this behavior in code. The environment variables are convenient when troubleshooting problems.
Endpoint Overrides
GOOGLE_CLOUD_CPP_LANGUAGE_SERVICE_ENDPOINT=...overrides theEndpointOption(which defaults to "language.googleapis.com") used byMakeLanguageServiceConnection().
GOOGLE_CLOUD_CPP_ENABLE_TRACING=rpc: turns on tracing for most gRPC calls. The library injects an additional Stub decorator that prints each gRPC request and response. Unless you have configured your own logging backend, you should also setGOOGLE_CLOUD_CPP_ENABLE_CLOGto produce any output on the program's console.
See Also
google::cloud::TracingComponentsOptionGOOGLE_CLOUD_CPP_TRACING_OPTIONS=...: modifies the behavior of gRPC tracing, including whether messages will be output on multiple lines, or whether string/bytes fields will be truncated.
See Also
google::cloud::GrpcTracingOptionsOptionGOOGLE_CLOUD_CPP_ENABLE_CLOG=yes: turns on logging in the library, basically the library always "logs" but the logging infrastructure has no backend to actually print anything until the application sets a backend or they set this environment variable.
[[["Easy to understand","easyToUnderstand","thumb-up"],["Solved my problem","solvedMyProblem","thumb-up"],["Other","otherUp","thumb-up"]],[["Hard to understand","hardToUnderstand","thumb-down"],["Incorrect information or sample code","incorrectInformationOrSampleCode","thumb-down"],["Missing the information/samples I need","missingTheInformationSamplesINeed","thumb-down"],["Other","otherDown","thumb-down"]],["Last updated 2025-09-04 UTC."],[[["\u003cp\u003eThis document provides version-specific documentation for the C++ language library, with the latest release candidate being version 2.37.0-rc and the oldest being 2.11.0.\u003c/p\u003e\n"],["\u003cp\u003eEnvironment variables can be used to configure the library's behavior, such as overriding the default endpoint using \u003ccode\u003eGOOGLE_CLOUD_CPP_LANGUAGE_SERVICE_ENDPOINT\u003c/code\u003e.\u003c/p\u003e\n"],["\u003cp\u003eTracing for gRPC calls can be enabled by setting \u003ccode\u003eGOOGLE_CLOUD_CPP_ENABLE_TRACING=rpc\u003c/code\u003e, and \u003ccode\u003eGOOGLE_CLOUD_CPP_ENABLE_CLOG\u003c/code\u003e should also be set to enable output to the console.\u003c/p\u003e\n"],["\u003cp\u003eThe variable \u003ccode\u003eGOOGLE_CLOUD_CPP_TRACING_OPTIONS\u003c/code\u003e is available to further customize gRPC tracing behavior, such as formatting and truncation options.\u003c/p\u003e\n"],["\u003cp\u003eWhile \u003ccode\u003eGOOGLE_CLOUD_PROJECT\u003c/code\u003e is used for GCP project configuration in examples and tests, it does not impact the behavior of the library itself.\u003c/p\u003e\n"]]],[],null,["Version 2.21.0keyboard_arrow_down\n\n- [2.42.0-rc (latest)](/cpp/docs/reference/language/latest/language-env)\n- [2.41.0](/cpp/docs/reference/language/2.41.0/language-env)\n- [2.40.0](/cpp/docs/reference/language/2.40.0/language-env)\n- [2.39.0](/cpp/docs/reference/language/2.39.0/language-env)\n- [2.38.0](/cpp/docs/reference/language/2.38.0/language-env)\n- [2.37.0](/cpp/docs/reference/language/2.37.0/language-env)\n- [2.36.0](/cpp/docs/reference/language/2.36.0/language-env)\n- [2.35.0](/cpp/docs/reference/language/2.35.0/language-env)\n- [2.34.0](/cpp/docs/reference/language/2.34.0/language-env)\n- [2.33.0](/cpp/docs/reference/language/2.33.0/language-env)\n- [2.32.0](/cpp/docs/reference/language/2.32.0/language-env)\n- [2.31.0](/cpp/docs/reference/language/2.31.0/language-env)\n- [2.30.0](/cpp/docs/reference/language/2.30.0/language-env)\n- [2.29.0](/cpp/docs/reference/language/2.29.0/language-env)\n- [2.28.0](/cpp/docs/reference/language/2.28.0/language-env)\n- [2.27.0](/cpp/docs/reference/language/2.27.0/language-env)\n- [2.26.0](/cpp/docs/reference/language/2.26.0/language-env)\n- [2.25.1](/cpp/docs/reference/language/2.25.1/language-env)\n- [2.24.0](/cpp/docs/reference/language/2.24.0/language-env)\n- [2.23.0](/cpp/docs/reference/language/2.23.0/language-env)\n- [2.22.1](/cpp/docs/reference/language/2.22.1/language-env)\n- [2.21.0](/cpp/docs/reference/language/2.21.0/language-env)\n- [2.20.0](/cpp/docs/reference/language/2.20.0/language-env)\n- [2.19.0](/cpp/docs/reference/language/2.19.0/language-env)\n- [2.18.0](/cpp/docs/reference/language/2.18.0/language-env)\n- [2.17.0](/cpp/docs/reference/language/2.17.0/language-env)\n- [2.16.0](/cpp/docs/reference/language/2.16.0/language-env)\n- [2.15.1](/cpp/docs/reference/language/2.15.1/language-env)\n- [2.14.0](/cpp/docs/reference/language/2.14.0/language-env)\n- [2.13.0](/cpp/docs/reference/language/2.13.0/language-env)\n- [2.12.0](/cpp/docs/reference/language/2.12.0/language-env)\n- [2.11.0](/cpp/docs/reference/language/2.11.0/language-env) \n\nEnvironment Variables\n=====================\n\nA number of environment variables can be used to configure the behavior of the library. There are also functions to configure this behavior in code. The environment variables are convenient when troubleshooting problems.\n\nEndpoint Overrides\n------------------\n\n- `GOOGLE_CLOUD_CPP_LANGUAGE_SERVICE_ENDPOINT=...` overrides the `EndpointOption` (which defaults to \"language.googleapis.com\") used by `MakeLanguageServiceConnection()`.\n\n###### See Also\n\n[`google::cloud::EndpointOption`](https://cloud.google.com/cpp/docs/reference/common/latest/structgoogle_1_1cloud_1_1EndpointOption.html)\n\nLogging\n-------\n\n`GOOGLE_CLOUD_CPP_ENABLE_TRACING=rpc`: turns on tracing for most gRPC calls. The library injects an additional Stub decorator that prints each gRPC request and response. Unless you have configured your own logging backend, you should also set `GOOGLE_CLOUD_CPP_ENABLE_CLOG` to produce any output on the program's console.\n\n###### See Also\n\n[`google::cloud::TracingComponentsOption`](https://cloud.google.com/cpp/docs/reference/common/latest/structgoogle_1_1cloud_1_1TracingComponentsOption.html)`GOOGLE_CLOUD_CPP_TRACING_OPTIONS=...`: modifies the behavior of gRPC tracing, including whether messages will be output on multiple lines, or whether string/bytes fields will be truncated.\n\n###### See Also\n\n[`google::cloud::GrpcTracingOptionsOption`](https://cloud.google.com/cpp/docs/reference/common/latest/structgoogle_1_1cloud_1_1GrpcTracingOptionsOption.html)`GOOGLE_CLOUD_CPP_ENABLE_CLOG=yes`: turns on logging in the library, basically the library always \"logs\" but the logging infrastructure has no backend to actually print anything until the application sets a backend or they set this environment variable.\n\n###### See Also\n\n[`google::cloud::LogBackend`](https://cloud.google.com/cpp/docs/reference/common/latest/classgoogle_1_1cloud_1_1LogBackend.html)\n\n###### See Also\n\n[`google::cloud::LogSink`](https://cloud.google.com/cpp/docs/reference/common/latest/classgoogle_1_1cloud_1_1LogSink.html)\n\nSetting the Default Project\n---------------------------\n\n`GOOGLE_CLOUD_PROJECT=...`: is used in examples and integration tests to configure the GCP project. This has no effect in the library."]]
