string$to,
string$subject,
string$message,
[array|string$additional_headers = []],
[string$additional_params = ""]
): bool
Sends an email.
Parameters
- to
-
Receiver, or receivers of the mail.
The formatting of this string must comply with RFC 2822. Some examples are: user@example.com user@example.com, anotheruser@example.com User <user@example.com> User <user@example.com>, Another User <anotheruser@example.com>
- subject
-
Subject of the email to be sent.
Caution:
Subject must satisfy RFC 2047.
- message
-
Message to be sent.
Each line should be separated with a CRLF (\r\n). Lines should not be larger than 70 characters.
Caution:
(Windows only) When PHP is talking to a SMTP server directly, if a full stop is found on the start of a line, it is removed. To counter-act this, replace these occurrences with a double dot.
<?php
$text = str_replace("\n.", "\n..", $text);
?> - additional_headers (optional)
-
String or array to be inserted at the end of the email header.
This is typically used to add extra headers (From, Cc, and Bcc). Multiple extra headers should be separated with a CRLF (\r\n). If outside data are used to compose this header, the data should be sanitized so that no unwanted headers could be injected.
If an array is passed, its keys are the header names and its values are the respective header values.
Note:
Before PHP 5.4.42 and 5.5.27, repectively, additional_headers did not have mail header injection protection. Therefore, users must make sure specified headers are safe and contains headers only. i.e. Never start mail body by putting multiple newlines.
Note:
When sending mail, the mail must contain a From header. This can be set with the additional_headers parameter, or a default can be set in php.ini.
Failing to do this will result in an error message similar to Warning: mail(): "sendmail_from" not set in php.ini or custom "From:" header missing. The From header sets also Return-Path when sending directly via SMTP (Windows only).
Note:
If messages are not received, try using a LF (\n) only. Some Unix mail transfer agents (most notably qmail) replace LF by CRLF automatically (which leads to doubling CR if CRLF is used). This should be a last resort, as it does not comply with RFC 2822.
- additional_params (optional)
-
The additional_params parameter can be used to pass additional flags as command line options to the program configured to be used when sending mail, as defined by the sendmail_path configuration setting. For example, this can be used to set the envelope sender address when using sendmail with the -f sendmail option.
This parameter is escaped by escapeshellcmd internally to prevent command execution. escapeshellcmd prevents command execution, but allows to add additional parameters. For security reasons, it is recommended for the user to sanitize this parameter to avoid adding unwanted parameters to the shell command.
Since escapeshellcmd is applied automatically, some characters that are allowed as email addresses by internet RFCs cannot be used. mail can not allow such characters, so in programs where the use of such characters is required, alternative means of sending emails (such as using a framework or a library) is recommended.
The user that the webserver runs as should be added as a trusted user to the sendmail configuration to prevent a 'X-Warning' header from being added to the message when the envelope sender (-f) is set using this method. For sendmail users, this file is /etc/mail/trusted-users.
Return Values
Returns true if the mail was successfully accepted for delivery, false otherwise.
It is important to note that just because the mail was accepted for delivery, it does NOT mean the mail will actually reach the intended destination.
Notes
Note:
The SMTP implementation (Windows only) of mail differs in many ways from the sendmail implementation. First, it doesn't use a local binary for composing messages but only operates on direct sockets which means a MTA is needed listening on a network socket (which can either on the localhost or a remote machine).
Second, the custom headers like From:, Cc:, Bcc: and Date: are not interpreted by the MTA in the first place, but are parsed by PHP.
As such, the to parameter should not be an address in the form of "Something <someone@example.com>". The mail command may not parse this properly while talking with the MTA.
Note:
It is worth noting that the mail function is not suitable for larger volumes of email in a loop. This function opens and closes an SMTP socket for each email, which is not very efficient.
For the sending of large amounts of email, see the PEAR::Mail, and PEAR::Mail_Queue packages.
Note:
The following RFCs may be useful: RFC 1896, RFC 2045, RFC 2046, RFC 2047, RFC 2048, RFC 2049, and RFC 2822.
Changelog
| Version | Description |
| 7.2.0 | The additional_headers parameter now also accepts an array. |