send-mail-function

send-mail-function is a variable defined in `sendmail.el'.
Its value is

sendmail-query-once

• This variable may be risky if used as a file-local variable.

Documentation:
Function to call to send the current buffer as mail.
The headers should be delimited by a line which is
not a valid RFC822 header or continuation line,
that matches the variable `mail-header-separator'.
This is used by the default mail-sending commands. See also
`message-send-mail-function' for use with the Message package.

You can customize this variable.

This variable was introduced, or its default value was changed, in version 24.1 of Emacs.