glenda.party
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PLUMB(2)                      System Calls Manual                     PLUMB(2)



NAME
       eplumb,  plumbfree,  plumbopen,  plumbsend, plumbsendtext, plumblookup,
       plumbpack,  plumbpackattr,   plumbaddattr,   plumbdelattr,   plumbrecv,
       plumbunpack,  plumbunpackpartial,  plumbunpackattr,  Plumbmsg   - plumb
       messages

SYNOPSIS
       #include <u.h>
       #include <libc.h>
       #include <plumb.h>

       int        plumbopen(char *port, int omode)

       int        plumbsend(int fd, Plumbmsg *m)

       int        plumbsendtext(int fd, char *src, char *dst, char *wdir, char
       *data)

       void       plumbfree(Plumbmsg *m)

       Plumbmsg*  plumbrecv(int fd)

       char*      plumbpack(Plumbmsg *m, int *np)

       Plumbmsg*  plumbunpack(char *buf, int n)

       Plumbmsg*  plumbunpackpartial(char *buf, int n, int *morep)

       char*      plumbpackattr(Plumbattr *a)

       Plumbattr* plumbunpackattr(char *a)

       char*      plumblookup(Plumbattr *a, char *name)

       Plumbattr* plumbaddattr(Plumbattr *a, Plumbattr *new)

       Plumbattr* plumbdelattr(Plumbattra *a, char *name)

       int        eplumb(int key, char *port)

DESCRIPTION
       These routines manipulate plumb(6) messages, transmitting them, receiv‐
       ing them, and converting them between text and these data structures:

              typedef
              struct Plumbmsg
              {
                    char      *src;
                    char      *dst;
                    char      *wdir;
                    char      *type;
                    Plumbattr *attr;
                    int       ndata;
                    char      *data;
              } Plumbmsg;

              typedef
              struct Plumbattr
              {
                    char      *name;
                    char      *value;
                    Plumbattr *next;
              } Plumbattr;

       Plumbopen opens the named plumb port, using  open(2)  mode  omode.   If
       port begins with a slash, it is taken as a literal file name; otherwise
       plumbopen searches for the location of the plumber(4) service and opens
       the port there.

       For  programs using the event(2) interface, eplumb registers, using the
       given key, receipt of messages from the named port.

       Plumbsend formats and writes message m to the file descriptor fd, which
       will usually be the result of plumbopen("send", OWRITE).  Plumbsendtext
       is a simplified version for text-only  messages;  it  assumes  type  is
       text, sets attr to nil, and sets ndata to strlen(data).

       Plumbfree  frees  all  the  data associated with the message m, all the
       components of which must therefore have been allocated with malloc(2).

       Plumbrecv returns the next message available on the file descriptor fd,
       or nil for error.

       Plumbpack  encodes  message  m  as  a character string in the format of
       plumb(6), setting *np to the length in bytes of the  string.   Plumbun‐
       pack does the inverse, translating the n bytes of buf into a Plumbmsg.

       Plumbunpackpartial enables unpacking of messages that arrive in pieces.
       The first call to plumbunpackpartial for a given message must be suffi‐
       cient  to unpack the header; subsequent calls permit unpacking messages
       with long data sections.  For each call, buf points to the beginning of
       the complete message received so far, and n reports the total number of
       bytes received for that message.  If the message is complete,  the  re‐
       turn  value  will be as in plumbunpack.  If not, and morep is not null,
       the return value will be nil and *morep will be set to  the  number  of
       bytes remaining to be read for this message to be complete (recall that
       the byte count is in the header).  Those bytes should be  read  by  the
       caller,  placed  at location buf+n, and the message unpacked again.  If
       an error is encountered, the return value will be nil and  *morep  will
       be zero.

       Plumbpackattr  converts the list a of Plumbattr structures into a null-
       terminated string.  If an attribute value contains white  space,  quote
       characters,  or equal signs, the value will be quoted appropriately.  A
       newline character will terminate processing.  Plumbunpackattr  converts
       the null-terminated string a back into a list of Plumbattr structures.

       Plumblookup  searches  the  Plumbattr  list a for an attribute with the
       given name and returns the associated value.  The  returned  string  is
       the original value, not a copy.  If the attribute has no value, the re‐
       turned value will be the empty string; if the attribute does not  occur
       in the list at all, the value will be nil.

       Plumbaddattr appends the new Plumbattr (which may be a list) to the at‐
       tribute list a and returns the new list.  Plumbattr searches the list a
       for  the  first  attribute with name name and deletes it from the list,
       returning the resulting list.  Plumbdelattr is a no-op if no  such  at‐
       tribute exists.

SOURCE
       /sys/src/libplumb

SEE ALSO
       plumb(1), event(2), plumber(4), plumb(6)

DIAGNOSTICS
       When  appropriate,  including when a plumbsend fails, these routine set
       errstr.



                                                                      PLUMB(2)