This application connects to your YugabyteDB instance via the libpq driver and performs basic SQL operations. The instructions below are provided for YugabyteDB Aeon deployments. If you use a different type of deployment, then update the sample-app.c file with proper connection parameters.

• A 32-bit (x86) or 64-bit (x64) architecture machine. Use Rosetta to build and run on the Apple silicon.
• gcc 4.1.2 or later, clang 3.4 or later installed.
• libpq driver.
• OpenSSL library (used by libpq to establish secured SSL connections).
• Command line tool or your favourite IDE, such as Visual Studio Code.

• Start YugabyteDB Aeon instance. You can use the free tier at no cost.
• Add an IP address of your machine/laptop to the IP allow list

Clone the repository and change dirs into it:

git clone https://github.com/YugabyteDB-Samples/yugabyte-simple-c-app.git && cd yugabyte-simple-c-app

Locate and define the following configuration-related macros in the sample-app.c file:

• HOST - the hostname of your instance.
• USER - the username for your instance.
• PASSWORD - the database password.
• SSL_MODE - the SSL mode to use. YugabyteDB Aeon requires SSL connections; use verify-full.
• SSL_ROOT_CERT - a full path to your CA root cert (for example, /Users/dmagda/certificates/root.crt).

Note, you can easily find all the settings on the YugabyteDB Aeon dashboard:

1. Install the libpq driver via Homebrew package manager or using a different method.

2. Replace the {libpq-install-dir} placeholder with your libpq installation root dir and build the application with gcc or clang:

   gcc sample-app.c -o sample-app -I{libpq-install-dir}/libpq/include -L{libpq-install-dir}/libpq/lib -lpq

3. Run the application:

   ./sample-app

Upon successful execution, you will see output similar to the following:

>>>> Connecting to YugabyteDB!
>>>> Connected to YugabyteDB!
>>>> Successfully created table DemoAccount.
>>>> Selecting accounts:
name = Jessica, age = 28, country = USA, balance = 10000
name = John, age = 28, country = Canada, balance = 9000
>>>> Transferred 800 between accounts.
>>>> Selecting accounts:
name = Jessica, age = 28, country = USA, balance = 9200
name = John, age = 28, country = Canada, balance = 9800

Congrats! You've successfully executed a simple C app that works with YugabyteDB.

Now, explore the source code of sample-app.c:

1. connect function - establishes a connection with your cloud instance via the libpq driver.
2. createDatabase function - creates a table and populates it with sample data.
3. selectAccounts function - queries the data with SQL SELECT statements.
4. transferMoneyBetweenAccounts function - updates records consistently with distributed transactions.

Having issues running this application or want to learn more from Yugabyte experts?

Join our Slack channel, or raise a question on StackOverflow and tag the question with yugabytedb!