1()                         PMDK Programmer's Manual                         ()
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NAME

6       pmem2_source_pread_mcsafe(), pmem2_source_pwrite_mcsafe() - read source
7       contents or write to the source in a safe manner
8

SYNOPSIS

10              #include <libpmem2.h>
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12              struct pmem2_source;
13              int pmem2_source_pread_mcsafe(struct pmem2_source *src, void *buf, size_t size,
14                      size_t offset);
15              int pmem2_source_pwrite_mcsafe(struct pmem2_source *src, void *buf, size_t size,
16                      size_t offset);
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DESCRIPTION

19       The pmem2_source_pread_mcsafe() function  reads  size  bytes  from  the
20       source  src  starting  at  offset  offset  into  the  buffer  buf.  The
21       pmem2_source_pwrite_mcsafe() function writes size bytes from the buffer
22       buf to the source src starting at the offset offset.
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24       Above  functions  are  capable of detecting bad blocks and handling the
25       SIGBUS signal thrown when accessing a bad block.  When a bad  block  is
26       encountered,  pmem2_source_pread_mcsafe()  and  pmem2_source_pwrite_mc‐
27       safe() functions return corresponding error.  A signal handler for SIG‐
28       BUS  signal  is  registered  using sigaction(2) for the running time of
29       those operations.  This capability is limited to POSIX systems.
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31       For  bad  block  detection  and   clearing,   see   pmem2_badblock_con‐
32       text_new(3), pmem2_badblock_next(3) and pmem2_badblock_clear(3).
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RETURN VALUE

35       The  pmem2_source_pread_mcsafe() and pmem2_source_pwrite_mcsafe() func‐
36       tions return 0 on success or a negative error code on failure.
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ERRORS

39       The pmem2_source_pread_mcsafe()  and  pmem2_source_pwrite_mcsafe()  can
40       fail with the following errors:
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42       • PMEM2_E_IO_FAIL - a physical I/O error occurred during the read/write
43         operation, a possible bad block encountered.
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45       • PMEM2_E_LENGTH_OUT_OF_RANGE - read/write  operation  size  size  from
46         offset offset goes beyond the file length.
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48       • PMEM2_E_SOURCE_TYPE_NOT_SUPPORTED - read/write operation doesn’t sup‐
49         port    provided    source,     only     sources     created     with
50         pmem2_source_from_fd(3)  and pmem2_source_from_handle(3) are support‐
51         ed.
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53       Those operations  can  also  return  all  errors  from  the  underlying
54       pread(2),  pwrite(2), sigaction(2) functions on POSIX systems and Read‐
55       File(), WriteFile() functions on Windows.
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SEE ALSO

58       pread(2), pwrite(2), ReadFile(), WriteFile(),  pmem2_badblock_clear(3),
59       pmem2_badblock_context_new(3),                  pmem2_badblock_next(3),
60       pmem2_source_from_fd(3), pmem2_source_from_handle(3),  libpmem2(7)  and
61       <https://pmem.io>
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65PMDK -                            2023-06-05                                ()
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