aws-sdk-cpp How to decrypt a password encrypted by kms using KMSCLIENT of c++ sdk - c++

Question

im trying to found any example to how decrypt a password encrypted by KMS, for example i have a RDS database password encrypted by KMS, i want to decrypt it in my aws-cpp-lambda function to connect to the database.
i see that for call client Decrypt i need a DecryptRequest;
but i don't know how to initialize it and where set my "encriptedPassword" in the DecryptedRequest to call client.Decrypt()
this is base64
encriptedPassword = "GPK0ujdAAAAZzBlBgkqhkiG"
Aws::SDKOptions options;
InitAPI(options);
{
Aws::Client::ClientConfiguration awsConfig;
awsConfig.region = Aws::Environment::GetEnv("AWS_REGION");
Aws::KMS::KMSClient client(awsConfig);
// Aws::KMS::Model::DecryptRequest decryptRequest;
// client.Decrypt(decryptRequest);
}
// shutdown the aws api
std::cout << "shutdown api" << "\n";
ShutdownAPI(options);
all the credentials are managed and storage by the aws administrator so i don't have access to that configuration, i only have the encrypted db password. when i make the lambda i publish it a git repository after that a jenkins process build and deploy the lambda to aws, jenkins has the credentials etc and i suppose that also is saved in the ec2 or aws config, they only give me a example of how to do that but its in nodejs i need to do a c++ version of that for example this is the nodejs example
use strict'
const AWS = require('aws-sdk');
module.exports.decrypt = (key) => {
return new Promise((resolve, reject) => {
const kms = new AWS.KMS();
console.log('Attempting to decrypt: ' + key);
const params = {CiphertextBlob: new Buffer(key, 'base64')};
console.log(params);
kms.decrypt(params, function (err, data) {
if (err) {
console.log('Error while decrypting key: ' + err);
reject(err)
} else {
console.log('Decrypted key');
resolve(data.Plaintext.toString('ascii'));
}
});
});
what nodejs version do is decrypt the password using sdk kms client after that is passed as simple string to the db connection lib and connect to the database using host, port, db name, etc.
what i need to do is decrypt the password using the KMSCLIENT for c++ like the node version.
anyone cant write a small example please. Thanks to all!!