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 the EndpointOption (which defaults to "speech.googleapis.com") used by MakeAdaptationConnection().
GOOGLE_CLOUD_CPP_SPEECH_ENDPOINT=... overrides the EndpointOption (which defaults to "
GOOGLE_CLOUD_CPP_SPEECH_ENDPOINT=... overrides the EndpointOption (which defaults to "speech.googleapis.com") used by MakeSpeechConnection().
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.
See Also
google::cloud::LoggingComponentsOptionGOOGLE_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"]],[["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complicated / too many steps","tooComplicatedTooManySteps","thumb-down"],["Out of date","outOfDate","thumb-down"],["Samples / code issue","samplesCodeIssue","thumb-down"],["Other","otherDown","thumb-down"]],["Last updated 2025-08-14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\u003eThis page documents the different versions of the C++ Speech library, listing versions from 2.37.0-rc (latest) down to 2.11.0.\u003c/p\u003e\n"],["\u003cp\u003eEnvironment variables are crucial for configuring the behavior of the C++ Speech library and are especially useful for troubleshooting.\u003c/p\u003e\n"],["\u003cp\u003e\u003ccode\u003eGOOGLE_CLOUD_CPP_ADAPTATION_ENDPOINT\u003c/code\u003e and \u003ccode\u003eGOOGLE_CLOUD_CPP_SPEECH_ENDPOINT\u003c/code\u003e environment variables can be used to override the default endpoints for the \u003ccode\u003eMakeAdaptationConnection()\u003c/code\u003e and \u003ccode\u003eMakeSpeechConnection()\u003c/code\u003e functions, respectively.\u003c/p\u003e\n"],["\u003cp\u003eTracing for gRPC calls can be enabled via \u003ccode\u003eGOOGLE_CLOUD_CPP_ENABLE_TRACING=rpc\u003c/code\u003e, and the output can be configured by setting \u003ccode\u003eGOOGLE_CLOUD_CPP_TRACING_OPTIONS\u003c/code\u003e.\u003c/p\u003e\n"],["\u003cp\u003eLogging can be enabled by setting \u003ccode\u003eGOOGLE_CLOUD_CPP_ENABLE_CLOG=yes\u003c/code\u003e, allowing the logging infrastructure to print to the program's console.\u003c/p\u003e\n"]]],[],null,[]]
