Temporary File

:::info[Note] This is a point-in-time snapshot of the API documentation from January 2026. Going forward, we will not be maintaining a public copy of these references, and recommend users to refer to the built-in signature helpers available in the Hack LSP instead for complete and up-to-date information. :::

Create a new temporary file

namespace HH\Lib\File;

function temporary_file(
  string $prefix = 'hack-tmp-',
  string $suffix = '',
): TemporaryFile;

The file is automatically deleted when the disposable is removed.

• If the prefix starts with ., it is interpreted relative to the current working directory.
• If the prefix statis with /, it is treated as an absolute path.
• Otherwise, it is created in the system temporary directory.

Regardless of the kind of prefix, the parent directory must exist.

A suffix can optionally be provided; this is useful when you need a particular filename extension; for example, File\temporary_file('foo', '.txt') may create /tmp/foo123456.txt.

The temporary file:

• will be a new file (i.e. O_CREAT | O_EXCL)
• be owned by the current user
• be created with mode 0600
• will be automatically deleted when the object is disposed

Parameters

• string $prefix = 'hack-tmp-'
• string $suffix = ''

Returns

• TemporaryFile