ZMAILER(3zm)                                                      ZMAILER(3zm)

       mail_open, mail_priority, mail_abort, mail_close, mail_close_alternate,
       mail_alloc, mail_free, mail_host - zmailer message submission interface


       #include <stdio.h>
       #include <zmailer.h>

       FILE *mail_open(char *)

       int mail_priority;

       int mail_abort(FILE *)

       int mail_close(FILE *)

       int mail_close_alternate(FILE *mfp, char *where, char *suffix)

       char *mail_alloc(unsigned int)

       int mail_free(char *)

       char *mail_host()

       The  main  program  against  which this library is liked is expected to
          char *progname;
       variable which carries a copy of argv[0] or something  else  that  pro-
       grammer wants to set.

       Linkage time: -lzmailer

       These  routines  may  be  used  by  any program wishing to submit mail.
       mail_open will return a FILE * to a message file that should be written
       to  by  the  application.   This message file contains three parts: the
       message envelope, the message header, and the message body.  The  exact
       format  of  these components depend on the message protocol, which must
       be specified as the parameter to mail_open.  The choices are  predeter-
       mined  by the capabilities of the mailer, and are defined in the header
       file.  The known possibilities are:

              this is the only format supported by default by the mailer.  The
              message headers and body in this format are defined by the DARPA
              Request For Comments 822 and 1123.  The message envelope  syntax
              is  similar  to  the  message  header  syntax,  but for complete
              details refer to the ZMailer documentation.

              intended for fax transmissions.

              intended for old style UUCP format message headers

              intended for X.400(88) messages.

       The mail_open() routine will look for FULLNAME and PRETTYLOGIN environ-
       ment variables and translate them into message envelope data for use by
       the mailer if it generates a sender address header for the message.

       Note that the return value from the mail_open() routine corresponds  to
       the  return  value of an fopen(3), and similarly the return values from
       mail_abort()  and  mail_close()  correspond  to  the  return  value  of

       The mail_priority variable has default value of 0, and is used on scan-
       ning Zmailer configuration variable ROUTERDIRS, which  tells  alternate
       router directories under the POSTOFFICE directory.  At value 0, ROUTER-
       DIRS variable is not used.  At higher values, successive directory from
       "ROUTERDIRS" is taken.  See below about Z-Environment.

       The  mail_close_alternate()  can be used to send currently open message
       file to some alternate destination, and is used at  smtpserver(8zm)  to
       send some quick-action requests directly to the scheduler(8zm).

       The  mail_alloc()  and  mail_free() routines are used to provide memory
       space for internal data structures.  The versions of these routines  in
       the  library  simply  call malloc(3) and free(3) but an application may
       override them if desired.

       Similarly the mail_host() routine is intended to return a unique string
       for  each host, by default the hostname, and this too is intended to be
       overridden by an application that may  already  have  this  information
       available in some form.

       The  message  envelope headers are used to carry meta-information about
       the message.  The goal is to carry transport-envelope information sepa-
       rate from message (RFC-822) headers, and body.
       At first the message starts with a set of envelope headers (*-prefix denotes optional):
                 *external \n
                 *rcvdfrom %s@%s (%s) \n
                 *bodytype %s \n
                 *with %s \n
                 *identinfo %s \n
                   from <%s> \n
                   channel error \n
                 *envid %s \n
                 *notaryret %s \n
       Then for each recipient pairs of:
                 *todsn [NOTIFY=...] [ORCPT=...] \n
                 to <%s> \n
       Just before the data starts, a magic entry:
                 env-end \n
       Then starts the message RFC-822 headers, and below it, the body

                 ... set up signal handlers ...
                 FILE *mfp = mail_open(MSG_RFC822,0);
                 if (mfp != NULL) {
                      ... output the mail message to mfp ...
                 } else
                      ... error handling for not being able to open the file ...
                 if (some application processing went wrong
                           || we took an interrupt)
                      (void) mail_abort(mfp);
                 else if (mail_close(mfp) == EOF)
                      ... error handling if something went wrong ...

              variable defines textual fullname, for example: "Sample User"

              variable defines user@node format of what user wants to claim as
              his/her  own  address  (it  must  match  those  of  mail  router



              Environment  variables picked up in sequence in order to find an
              idea about user's identity to be stored into a line like:

                recvfrom STDIN (username@hostname)

              which is purely cosmetic documenting thing.

              defines directory where all POSTOFFICE functions are under.
              Example: POSTOFFICE=/var/spool/postoffice

              defines a `:' separated list of  alternate  router  directories.
              If  these  are  defined  at  all,  they must exist, if alternate
              queueing priority mechanism is desired to be used.
              Example: ROUTERDIRS=router1:router2:router3:router4

              Value ``1'' at this variable means that all  router  directories
              must have subdirectories with names ``A'' thru ``Z'', alike

              defines  an  AF_UNIX/DGRAM  type  local notification socket into
              which a receiving client may inform the router(8zm)  that  there
              is some new job available.

              Presence of this ZENV-variable means that messages will be tried
              to be stored into these alternate directories (syntax alike with
              ROUTERDIRS  !)   so  that  it can be leisurely analyzed (by e.g.
              virus scanners) before feeding it onwards to virus scanners.

              Presence of this also activates checking  of  INPUTDIRHASH,  and

              This is analogous to ROUTERDIRHASH.

              This is analogous to ROUTERNOTIFY.





       sendmail(8zm), zmailer(1zm), zmailer.conf(5zm).

       This program authored and copyright by:
          Rayan Zachariassen <no address>
       ROUTERDIRS mechanism is by:
          Matti Aarnio <>

                                  2003-Aug-28                     ZMAILER(3zm)