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C Driver

Get Started with the C Driver

On this page

  • Overview
  • Download and Install
  • Download the C Driver
  • Create a MongoDB Deployment
  • Create a Free MongoDB deployment on Atlas
  • Save your Credentials
  • Create a Connection String
  • Find Your MongoDB Atlas Connection String
  • Copy Your Connection String
  • Update the Placeholders
  • Run a Sample Query
  • Create a Project Directory
  • Create Your C Driver Application
  • Assign the Connection String
  • Run Your C Application
  • Next Steps

Overview

The MongoDB C Driver is a C library that you can use to connect to MongoDB and interact with data stored in your deployment. This guide shows you how to create an application that uses the C driver to connect to a MongoDB cluster hosted on MongoDB Atlas and query data in your cluster.

Tip

MongoDB Atlas is a fully managed cloud database service that hosts your MongoDB deployments. You can create your own free (no credit card required) MongoDB Atlas deployment by following the steps in this guide.

Follow this guide to connect a sample C application to a MongoDB Atlas deployment. If you prefer to connect to MongoDB using a different driver or programming language, see our list of official drivers.

Download and Install

Download the C Driver

The C driver consists of two libraries: libbson and libmongoc. In this guide, you will learn how to install libmongoc, which comes bundled with libbson.

You can install the C driver by using a package manager, or by installing the libraries from source. Different Linux distributions install different versions of the driver when installed with a package manager. Because of this, you should check the version your distribution includes before installing the driver.

On RedHat Enterprise Linux (RHEL) distributions, you can check the version by running the following command in your shell:

sudo dnf info mongo-c-driver-devel

On Debian-based distributions, you can check the version by running the following command in your shell:

apt-cache policy libmongoc-dev

If the version of the driver that is available is not the version you want, you can install the driver from source. To learn how to install the driver from source, see the Building the C Driver Libraries from Source guide.

To learn how to install the driver by using a package manager, select the tab corresponding to your operating system:

RedHat Enterprise Linux Distributions

You can install the driver on RedHat Enterprise Linux (RHEL) distributions, version 7 or later, or distributions based on RHEL, such as:

Before you install the driver on a RHEL distribution, not including Fedora, you must first enable the Extra Packages for Enterprise Linux (EPEL) repository. You can enable the EPEL repository by installing the epel-release package, as shown in the following example:

yum install epel-release

Then, you can install the C driver by using yum. To do so, run the following command in your shell:

yum install mongo-c-driver-devel

Note

Developer Packages

The preceding code example installs the developer packages, which are required to build applications that use the C driver. To install only the libraries, without development files, run the following command:

yum install mongo-c-driver

If you are installing on a RHEL distribution that is version 8 or later, we recommend running the preceding code examples by using dnf instead of yum.

Fedora

If you are using Fedora or an enterprise Linux distribution of version 8 or later, you can install the driver by using the same commands as shown in the preceding example and replacing yum with dnf.

The following example shows how to install the C driver in a Fedora distribution:

dnf install mongo-c-driver-devel

Debian-Based Distributions

In Debian-Based Linux distributions, including Ubuntu and Ubuntu derivatives, the driver libraries are available through the Advanced Packaging Tool (APT). You can install the driver with APT by running the following command in your shell:

apt install libmongoc-dev

The preceding code example installs the developer packages, which are required to build applications that use the C driver. To install only the libraries, without development files, run the following command:

apt install libmongoc-1.0-0

For Windows environments, we recommend building the C driver libraries from source to ensure maximum compatibility with the local toolchain. You can automate building from source by using a from-source library package management tool, such as vcpkg.

Tip

To learn how to get started with vcpkg, see the vcpkg Get Started guide in the Microsoft documentation.

In vcpkg manifest mode, add the driver library to your project's vcpkg.json manifest file, as shown in the following example:

{
   // ...
   "dependencies": [
     // ...
     "mongo-c-driver"
   ]
}

When you build a CMake project with vcpkg integration and have a vcpkg.json manifest file, vcpkg automatically installs the project's dependencies before proceeding with configuration.

If you are using vcpkg classic mode, you can install the driver by running the following command in your shell:

vcpkg install mongo-c-driver

After you install the driver, the standard CMake configuration file is available, as well as the generated IMPORTED targets. You can create a CMakeLists.txt file as shown in the following example:

find_package(mongoc-1.0 CONFIG REQUIRED)
target_link_libraries(my-application
    PRIVATE $<IF:$<TARGET_EXISTS:mongo::mongoc_shared>,mongo::mongoc_shared,mongo::mongoc_static>)

Note

You can use the $<IF:$<TARGET_EXISTS...>:...> generator expression in the preceding example to switch the link type of libmongoc based on the form that is available from the find_package() command. libmongoc supports building with both dynamic and static library types, but vcpkg installs only one type at a time.

To configure the CMake project with vcpkg integration, set the CMake toolchain file in the configuration command by running the following commands in your shell:

cmake -S . -B _build -D
CMAKE_TOOLCHAIN_FILE=$VCPKG_ROOT/scripts/buildsystems/vcpkg.cmake

You can download the C driver on MacOS by using the Homebrew package manager. To do so, run the following command in your shell:

brew install mongo-c-driver

After you complete these steps, you have the C driver installed on your machine.

Create a MongoDB Deployment

You can create a free tier MongoDB deployment on MongoDB Atlas to store and manage your data. MongoDB Atlas hosts and manages your MongoDB database in the cloud.

1

Create a Free MongoDB deployment on Atlas

Complete the Get Started with Atlas guide to set up a new Atlas account and load sample data into a new free tier MongoDB deployment.

2

Save your Credentials

After you create your database user, save that user's username and password to a safe location for use in an upcoming step.

After you complete these steps, you have a new free tier MongoDB deployment on Atlas, database user credentials, and sample data loaded into your database.

Create a Connection String

You can connect to your MongoDB deployment by providing a connection URI, also called a connection string, which instructs the driver on how to connect to a MongoDB deployment and how to behave while connected.

The connection string includes the hostname or IP address and port of your deployment, the authentication mechanism, user credentials when applicable, and connection options.

To connect to an instance or deployment not hosted on Atlas, see the Choose a Connection Target guide.

1

Find Your MongoDB Atlas Connection String

To retrieve your connection string for the deployment that you created in the previous step, log in to your Atlas account and navigate to the Database section and click the Connect button for your new deployment.

The connect button in the clusters section of the Atlas UI

Proceed to the Connect your application section and select "C" from the Driver selection menu and the version that best matches the version you installed from the Version selection menu.

Select the Password (SCRAM) authentication mechanism.

Deselect the Include full driver code example option to view only the connection string.

2

Copy Your Connection String

Click the button on the right of the connection string to copy it to your clipboard, as shown in the following screenshot:

The copy button next to the connection string in the Atlas UI
3

Update the Placeholders

Paste this connection string into a file in your preferred text editor and replace the <db_username> and <db_password> placeholders with your database user's username and password.

Save this file to a safe location for use in the next step.

After completing these steps, you have a connection string that corresponds to your Atlas cluster.

Run a Sample Query

After you complete these steps, you have a working application that uses the driver to connect to your MongoDB deployment, runs a query on the sample data, and prints out the result.

Next Steps

Congratulations on completing the quick start tutorial!

Note

If you run into issues in this tutorial, ask for help in the MongoDB Community Forums or submit feedback by using the Rate this page tab on the right or bottom right side of this page.

In this tutorial, you created a C application that connects to a MongoDB deployment hosted on MongoDB Atlas and retrieves a document that matches a query.

Learn more about the C driver from the following resources:

Back

Asynchronous C Driver: Public Preview

Next

Connect to MongoDB