---
name: "unblock"
section: "3abz"
platform: "linux"
package: "libabz0-dev"
version: "0.5.1"
release: "Debian 3.1 (Sarge)"
platforms: ["linux"]
url: "https://new.carta.tech/unblock"
---

# unblock(3abz)

set sync/async I/O operations on a file descriptor.

## NAME

block, unblock - set sync/async I/O operations on a file descriptor.

## LIBRARIES

Abz Library (-labz), Debug Library (-ldebug)

## SYNOPSIS

```
#include <abz/unblock.h>

int block(int fd);
int unblock(int fd);
```

## DESCRIPTION

The **block()** function sets synchronous I/O operations on the specified file descriptor *fd*. The **unblock()** function sets asynchronous I/O operations on the specified file descriptor *fd*.

## NOTES

None of the libabz routines are thread-safe. I'm not planning to change this either! For more information, please see http://threading.2038bug.com/

## AUTHOR

Written by Abraham vd Merwe \<abz@blio.com\>