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_ADAPTATION_ENDPOINT=...overrides theEndpointOption(which defaults to "speech.googleapis.com") used byMakeAdaptationConnection().
GOOGLE_CLOUD_CPP_SPEECH_ENDPOINT=...overrides theEndpointOption(which defaults to "speech.googleapis.com") used byMakeSpeechConnection().
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\u003eThe latest stable release is version 2.36.0, with a release candidate version 2.37.0-rc also available, while the current document version is at 2.21.0.\u003c/p\u003e\n"],["\u003cp\u003eThis page provides documentation for environment variables that configure the library's behavior, with functions to adjust these settings in code.\u003c/p\u003e\n"],["\u003cp\u003eEnvironment variables such as \u003ccode\u003eGOOGLE_CLOUD_CPP_ADAPTATION_ENDPOINT\u003c/code\u003e and \u003ccode\u003eGOOGLE_CLOUD_CPP_SPEECH_ENDPOINT\u003c/code\u003e can override default endpoint options for specific connections.\u003c/p\u003e\n"],["\u003cp\u003eLogging and tracing can be enabled using \u003ccode\u003eGOOGLE_CLOUD_CPP_ENABLE_TRACING\u003c/code\u003e and \u003ccode\u003eGOOGLE_CLOUD_CPP_ENABLE_CLOG\u003c/code\u003e, allowing for detailed monitoring of gRPC calls and library operations.\u003c/p\u003e\n"],["\u003cp\u003eThe environment variable \u003ccode\u003eGOOGLE_CLOUD_PROJECT\u003c/code\u003e is utilized in examples and tests for project configuration but does not directly impact the library's functionality.\u003c/p\u003e\n"]]],[],null,["Version 2.21.0keyboard_arrow_down\n\n- [2.42.0-rc (latest)](/cpp/docs/reference/speech/latest/speech-env)\n- [2.41.0](/cpp/docs/reference/speech/2.41.0/speech-env)\n- [2.40.0](/cpp/docs/reference/speech/2.40.0/speech-env)\n- [2.39.0](/cpp/docs/reference/speech/2.39.0/speech-env)\n- [2.38.0](/cpp/docs/reference/speech/2.38.0/speech-env)\n- [2.37.0](/cpp/docs/reference/speech/2.37.0/speech-env)\n- [2.36.0](/cpp/docs/reference/speech/2.36.0/speech-env)\n- [2.35.0](/cpp/docs/reference/speech/2.35.0/speech-env)\n- [2.34.0](/cpp/docs/reference/speech/2.34.0/speech-env)\n- [2.33.0](/cpp/docs/reference/speech/2.33.0/speech-env)\n- [2.32.0](/cpp/docs/reference/speech/2.32.0/speech-env)\n- [2.31.0](/cpp/docs/reference/speech/2.31.0/speech-env)\n- [2.30.0](/cpp/docs/reference/speech/2.30.0/speech-env)\n- [2.29.0](/cpp/docs/reference/speech/2.29.0/speech-env)\n- [2.28.0](/cpp/docs/reference/speech/2.28.0/speech-env)\n- [2.27.0](/cpp/docs/reference/speech/2.27.0/speech-env)\n- [2.26.0](/cpp/docs/reference/speech/2.26.0/speech-env)\n- [2.25.1](/cpp/docs/reference/speech/2.25.1/speech-env)\n- [2.24.0](/cpp/docs/reference/speech/2.24.0/speech-env)\n- [2.23.0](/cpp/docs/reference/speech/2.23.0/speech-env)\n- [2.22.1](/cpp/docs/reference/speech/2.22.1/speech-env)\n- [2.21.0](/cpp/docs/reference/speech/2.21.0/speech-env)\n- [2.20.0](/cpp/docs/reference/speech/2.20.0/speech-env)\n- [2.19.0](/cpp/docs/reference/speech/2.19.0/speech-env)\n- [2.18.0](/cpp/docs/reference/speech/2.18.0/speech-env)\n- [2.17.0](/cpp/docs/reference/speech/2.17.0/speech-env)\n- [2.16.0](/cpp/docs/reference/speech/2.16.0/speech-env)\n- [2.15.1](/cpp/docs/reference/speech/2.15.1/speech-env)\n- [2.14.0](/cpp/docs/reference/speech/2.14.0/speech-env)\n- [2.13.0](/cpp/docs/reference/speech/2.13.0/speech-env)\n- [2.12.0](/cpp/docs/reference/speech/2.12.0/speech-env)\n- [2.11.0](/cpp/docs/reference/speech/2.11.0/speech-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_ADAPTATION_ENDPOINT=...` overrides the `EndpointOption` (which defaults to \"speech.googleapis.com\") used by `MakeAdaptationConnection()`.\n- `GOOGLE_CLOUD_CPP_SPEECH_ENDPOINT=...` overrides the `EndpointOption` (which defaults to \"speech.googleapis.com\") used by `MakeSpeechConnection()`.\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."]]
