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);
       ssize_t lc_syncfilehash(lc_ctx_t *lctx, unsigned char *hash, const char *dst,
                       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() function synchronizes the file at pathname with with data fetched from the network. The
       file will be created if it does not exist.

       The lc_syncfile_hash() function synchronizes the file  at  pathname  with  with  data  fetched  from  the
       network.  The  file will be created if it does not exist. If a trailing slash is present it is parsed and
       removed before calling lc_syncfile(3).  Similar to rsync(3), the presence of  a  trailing  slash  on  the
       source  directory  indicates that the directories synced are at the same level. The absence of a trailing
       slash on the source will cause the directory to be created as a subdirectory on the destination.

       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)

LIBRECAST                                          2025-06-09                                         LC_SYNC(3)