string $file - The file name or the data itself
string $c_type - The content type of the image or file.
string $name - The suggested file name for the data. Only used, if $file contains data.
boolean $isfile - Whether $file is a file name or not.
string $encoding - Type of transfer encoding to use for the file data. Defaults is "base64". For text based files (eg. scripts/html etc.) this could be given as "quoted-printable".
Table 52-1. Possible PEAR_Error values
|Error code||Error message||Reason||Solution|
|NULL||"File is not readable file_name"||The file was not found or the script has not enough rights to access the file.||Check the file name and path. Check user and file permissions.|
|NULL||"Could not open file_name"||The file is already opened and exclusivly locked by another application.||In the most cases a program opens the file for writing. addAttachment() does no file locking, so this problem is not caused by competitive callings of this function.|