1 .\" Copyright (C) 1999 Joseph Samuel Myers.
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4 .\" manual provided the copyright notice and this permission notice are
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17 .\" which is licensed free of charge, as they might when working
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23 .TH PREAD 2 2008-120-3 "Linux" "Linux Programmer's Manual"
25 pread, pwrite \- read from or write to a file descriptor at a given offset
27 .B #define _XOPEN_SOURCE 500
29 .B #include <unistd.h>
31 .BI "ssize_t pread(int " fd ", void *" buf ", size_t " count \
34 .BI "ssize_t pwrite(int " fd ", const void *" buf ", size_t " count \
40 bytes from file descriptor
44 (from the start of the file) into the buffer starting at
46 The file offset is not changed.
51 bytes from the buffer starting at
53 to the file descriptor
57 The file offset is not changed.
59 The file referenced by
61 must be capable of seeking.
63 On success, the number of bytes read or written is returned (zero
64 indicates that nothing was written, in the case of
67 end of file, in the case of
69 or \-1 on error, in which case
71 is set to indicate the error.
76 to any error specified for
83 to any error specified for
92 system calls were added to Linux in
93 version 2.1.60; the entries in the i386 system call table were added
95 The libc support (including emulation using
97 on older kernels without the system calls) was added in glibc 2.1.
104 .BR feature_test_macros (7)