1()                         PMDK Programmer's Manual                         ()
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NAME

6       pmemlog_tell()(DEPRECATED),     pmemlog_rewind()(DEPRECATED),     pmem‐
7       log_walk()(DEPRECATED) - checks current write  point  for  the  log  or
8       walks through the log
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SYNOPSIS

11              #include <libpmemlog.h>
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13              long long pmemlog_tell(PMEMlogpool *plp);
14              void pmemlog_rewind(PMEMlogpool *plp);
15              void pmemlog_walk(PMEMlogpool *plp, size_t chunksize,
16                  int (*process_chunk)(const void *buf, size_t len, void *arg),
17                  void *arg);
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DESCRIPTION

20       The  pmemlog_tell()  function  returns  the current write point for the
21       log, expressed as a byte offset into the usable log space in the memory
22       pool.   This  offset  starts off as zero on a newly-created log, and is
23       incremented by each successful append operation.  This function can  be
24       used to determine how much data is currently in the log.
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26       The  pmemlog_rewind()  function  resets the current write point for the
27       log to zero.  After this call, the next append adds to the beginning of
28       the log.
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30       The  pmemlog_walk()  function walks through the log plp, from beginning
31       to end, calling the callback function process_chunk for each  chunksize
32       block  of  data found.  The argument arg is also passed to the callback
33       to help avoid the need for global state.   The  chunksize  argument  is
34       useful  for logs with fixed-length records and may be specified as 0 to
35       cause a single call to the callback with the entire log contents passed
36       as the buf argument.  The len argument tells the process_chunk function
37       how much data buf is holding.  The callback function should return 1 if
38       pmemlog_walk()  should continue walking through the log, or 0 to termi‐
39       nate the walk.  The callback function is called while holding  libpmem‐
40       log(7)  internal locks that make calls atomic, so the callback function
41       must not try to append to the log itself or deadlock will occur.
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RETURN VALUE

44       On success, pmemlog_tell() returns the current write point for the log.
45       On error, it returns -1 and sets errno appropriately.
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47       The pmemlog_rewind() and pmemlog_walk() functions return no value.
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SEE ALSO

50       libpmemlog(7) and <https://pmem.io>
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54PMDK -                            2023-06-05                                ()
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