Is it possible to override internal function?

I'd like to create PECL module which could replace mail() function. The new function would use SMTP protocol. I can't call any external utilities so this is the only posibility to send the mails. The environment is shared hosting platform so there are some limits, like forbidding the calling suid-ed binaries (like /usr/sbin/sendmail) and low number of user processes. This have to be hidden implementation so the users won't need to change their code, especially calling of mail() function. Is it possible to override the internal function in additional module? -- .''`. Piotr Roszatycki, Netia SA : :' : mailto:Piotr_Roszatycki@netia.net.pl . ' mailto:dexter@debian.org `-