io\_uring\_prep\_fallocate(3) liburing Manual io\_uring\_prep\_fallocate(3)

# [NAME](#NAME)

io\_uring\_prep\_fallocate - prepare a fallocate request

# [SYNOPSIS](#SYNOPSIS)

```
#include <fcntl.h>
#include <liburing.h>
```

```
void io_uring_prep_fallocate(struct io_uring_sqe *sqe,
                             int fd,
                             int mode,
                             __u64 offset,
                             __u64 len);
```

# [DESCRIPTION](#DESCRIPTION)

The [**io\_uring\_prep\_fallocate**(3)](/man/os/liburing/io_uring_prep_fallocate.3) function prepares a fallocate request. The submission queue entry *sqe* is setup to use the file descriptor pointed to by *fd* to start a fallocate operation described by *mode* at offset *offset* and *len* length in bytes.

This function prepares an async [**fallocate**(2)](/man/os/liburing/fallocate.2) request. See that man page for details.

# [RETURN VALUE](#RETURN_VALUE)

None

# [ERRORS](#ERRORS)

The CQE *res* field will contain the result of the operation. See the related man page for details on possible values. Note that where synchronous system calls will return **-1** on failure and set *errno* to the actual error value, io\_uring never uses *errno*. Instead it returns the negated *errno* directly in the CQE *res* field.

# [SEE ALSO](#SEE_ALSO)

[**io\_uring\_get\_sqe**(3)](/man/os/liburing/io_uring_get_sqe.3), [**io\_uring\_submit**(3)](/man/os/liburing/io_uring_submit.3), [**fallocate**(2)](/man/os/liburing/fallocate.2)

March 13, 2022 liburing-2.2

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Document: io_uring_prep_fallocate(3) from liburing 2.15-r5 (Chainguard OS)
Source: https://github.com/axboe/liburing.git