Filesystem Functions
PHP Manual


(PHP 4, PHP 5, PHP 7)

tempnamCreate file with unique file name


string tempnam ( string $dir , string $prefix )

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.



The directory where the temporary filename will be created.


The prefix of the generated temporary filename.

Note: Windows uses only the first three characters of prefix.

Return Values

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


Version Description
4.0.3 This function's behavior changed in 4.0.3. The temporary file is also created to avoid a race condition where the file might appear in the filesystem between the time the string was generated and before the script gets around to creating the file. Note, that you need to remove the file in case you need it no more, it is not done automatically.


Example #1 tempnam() example


$handle fopen($tmpfname"w");
fwrite($handle"writing to tempfile");

// do here something



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

See Also

Filesystem Functions
PHP Manual