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".
Return value
boolean - Returns TRUE on success,
PEAR_Error on failure.
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 programm opens the file for writing.
addAttachment() does no file locking, so this problem is
not caused by competitve callings of this function.
