NAME

       lc_sync, lc_syncfile - synchronize memory or files over multicast

LIBRARY

       Librecast library (liblibrecast, -llibrecast)

SYNOPSIS

       #include <librecast/sync.h>

       ssize_t lc_sync(lc_ctx_t *lctx, unsigned char *hash, void *data, const size_t len,
                       q_t *q, lc_stat_t *stats, lc_sync_options_t *opt, int flags);
       ssize_t lc_syncfile(lc_ctx_t *lctx, unsigned char *hash, const char *pathname,
                       q_t *q, lc_stat_t *stats, lc_sync_options_t *opt, int flags);

       Compile and link with -llibrecast.

DESCRIPTION

       The  lc_sync() function synchronizes the memory area pointed to by data of length len with
       data fetched from the network.

       The lc_syncfile() synchronizes the file at  pathname  with  with  data  fetched  from  the
       network. The file will be created if it does not exist.

       hash  is  used  to create the multicast address from which to fetch the merkle tree of the
       source data.  This tree is compared to the merkle tree of the memory at data to find which
       chunks  differ, and these chunks are fetched from the network using their hashes to create
       the multicast source addresses.

       lctx is a Librecast context, created with lc_ctx_new(3).

       If q is not NULL, it must point to a  queue  q_t  structure  previously  initialized  with
       q_init(3).  This queue will have jobs enqueued to build the tree. This is normally used in
       conjunction with a threadpool created  with  q_pool_create(3)  with  threads  all  calling
       q_job_seek(3).

       If  q  is  NULL,  the  creation  and destruction of a queue and threadpool will be handled
       automatically.

       If stats is not NULL, transfer statistics will be returned in this structure.

       opt is not used, at present, and must be NULL for compatibility with future versions.

       flags is not used, at present, and must be zero for compatibility with future versions.

RETURN VALUE

       These calls return the number of bytes received, or -1 if an error  occurred.   On  error,
       NULL is returned, and errno is set to indicate the error.

ERRORS

       EINVAL Invalid argument.

       ENOMEM Not enough space/cannot allocate memory (POSIX.1-2001).

       EACCES Permission to create a socket of the specified type and/or protocol is denied.

       lc_syncfile() can also fail with any of the errors for lc_mmapfile(3).

NOTES

       To  restrict  syncing  to  a  particular  network interface, call lc_ctx_ifx(3) to set the
       default interface for the Librecast context before calling the appropriate sync function.

SEE ALSO

       lc_ctx_new(3), lc_ctx_ifx(3),  lc_mmapfile(3),  lc_share(3),  mdex_init(3),  mdex_free(3),
       mdex_add(3),   mdex_addfile(3),   mdex_alias(3),  mdex_get(3),  mdex_put(3),  mdex_del(3),
       lcrq(7)