Create file with unique file name

# tempnam

(PHP 4, PHP 5, PHP 7, PHP 8)

tempnam — Create file with unique file name

### Description

tempnam(string `$directory`, string `$prefix`): string|false

Creates a file with a unique filename, with access permission set to 0600, in the specified directory. If the directory does not exist or is not writable, tempnam() may generate a file in the system's temporary directory, and return the full path to that file, including its name.

### Parameters

`directory`

  The directory where the temporary filename will be created.

`prefix`

  The prefix of the generated temporary filename.

  > Note: Only the first 63 characters of the prefix are used, the rest are ignored. Windows uses only the first three characters of the prefix.

### Return Values

Returns the new temporary filename (with path), or `false` on failure.

### Changelog

Version | Description
--- | ---
7.1.0 | tempnam() now emits a notice when falling back to the temp directory of the system.

### Examples

Example #1 tempnam() example

`<?php
$tmpfname = tempnam("/tmp", "FOO");
$handle = fopen($tmpfname, "w");
fwrite($handle, "writing to tempfile");
fclose($handle);
// do something here
unlink($tmpfname);
?>`

### Notes

> Note: If PHP cannot create a file in the specified `directory` parameter, it falls back on the system default. On NTFS this also happens if the specified `directory` contains more than 65534 files.

### See Also

- tmpfile() - Creates a temporary file
- sys_get_temp_dir() - Returns directory path used for temporary files
- unlink() - Deletes a file

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