# hiredis guide (C)

```json metadata
{
  "title": "hiredis guide (C)",
  "description": "Connect your C application to a Redis database.",
  "categories": ["docs","develop","stack","oss","rs","rc","oss","kubernetes","clients"],
  "tableOfContents": {"sections":[{"id":"build-and-install","title":"Build and install"},{"id":"connect-and-test","title":"Connect and test"},{"id":"more-information","title":"More information"}]}
}
```














[`hiredis`](https://github.com/redis/hiredis) is the
[C language](https://en.wikipedia.org/wiki/C_(programming_language))
client for Redis.
The sections below explain how to install `hiredis` and connect your application
to a Redis database.

`hiredis` requires a running Redis or [Redis Stack](https://redis.io/docs/latest/operate/oss_and_stack/install/install-stack/) server. See [Getting started](https://redis.io/docs/latest/operate/oss_and_stack/install/) for Redis installation instructions.

## Build and install

Clone or download the `hiredis` source from the [Github repository](https://github.com/redis/hiredis).
Then, in a terminal, go into the `hiredis` folder and run the `make` command to build
the dynamically-loaded library for `hiredis` (this has the name `libhiredis.dylib` on
MacOS and `libhiredis.so` on Linux). You can copy this library to your
project folder or run `sudo make install` to install it to `/usr/local/lib`.

## Connect and test

The code in the example below connects to the server, stores and retrieves
a string key using [`SET`](https://redis.io/docs/latest/commands/set) and
[`GET`](https://redis.io/docs/latest/commands/get), and then finally closes the
connection. An explanation of the code follows the example.




For a real project, you would build your code with a makefile, but for
this simple test, you can just place it in a file called `main.c` and
build it with the following command. (If you didn't install `hiredis`
using `make install`, then you should also use the `-I` option to
specify the folder that contains the `hiredis` headers.)

```bash
cc main.c -L/usr/local/lib -lhiredis
```

The default executable filename is `a.out`. If you run this file from
the terminal, you should see the following output:

```
% ./a.out                             
Reply: OK
Reply: bar
```

The code first uses `redisConnect()` to open the connection for
all subsequent commands to use. See
[Connect](https://redis.io/docs/latest/develop/clients/hiredis/connect) for
more information about connecting to Redis.

The `redisCommand()` function
issues commands to the server, each of which returns a
`redisReply` pointer. Here, the reply is a string, which you can
access using the `str` field of the reply. The `redisCommand()`
call allocates memory for the reply, so you should free this
with `freeReplyObject()` when you have finished using it.
See [Issue commands](https://redis.io/docs/latest/develop/clients/hiredis/issue-commands)
and [Handle replies](https://redis.io/docs/latest/develop/clients/hiredis/handle-replies)
for more information.

Finally, you should close the connection to Redis with a
call to `redisFree()`. This is not strictly necessary
for this short test program, but real-world code will typically
open and use many connections. You must free them after using them
to prevent errors.

## More information

The [`hiredis`](https://github.com/redis/hiredis) Github repository contains
examples and details that may be useful if you are using `hiredis` to
implement a higher-level client for another programming language. There are
also examples showing how to use `hiredis` adapter headers to integrate with
various event handling frameworks.

See the other pages in this section for more information and examples.