Unless otherwise configured, the client libraries use Application Default Credentials to authenticate with Google Cloud Services. While this works for most applications, in some cases you may need to override this default. You can do so by providing the UnifiedCredentialsOption The following example shows how to explicitly load a service account key file:
[](std::string const& keyfile) {
auto is = std::ifstream(keyfile);
is.exceptions(std::ios::badbit); // Minimal error handling in examples
auto contents = std::string(std::istreambuf_iterator<char>(is.rdbuf()), {});
auto options =
google::cloud::Options{}.set<google::cloud::UnifiedCredentialsOption>(
google::cloud::MakeServiceAccountCredentials(contents));
return google::cloud::texttospeech_v1::TextToSpeechClient(
google::cloud::texttospeech_v1::MakeTextToSpeechConnection(options));
}
[[["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 2025-03-14 UTC."],[[["This page provides documentation for overriding default authentication credentials when using the C++ client libraries for Google Cloud's Text-to-Speech service, specifically focusing on version 2.23.0 and up to the release candidate 2.37.0-rc."],["The libraries typically use Application Default Credentials for authentication, but users can override this by providing a `UnifiedCredentialsOption`, as demonstrated in the example."],["The provided example demonstrates loading authentication details from a service account key file using `MakeServiceAccountCredentials` to authenticate the `TextToSpeechClient` when default credentials are not used."],["The page contains a list of available versions, from 2.23.0 to the most recent release candidate 2.37.0-rc, for the C++ TextToSpeech service, each with a link to its documentation regarding authentication overrides."],["For more information on different methods for generating `google::cloud::Credentials` objects, users are directed to the Authentication Components section."]]],[]]