blob: 689799c42580150eeb85bc7a5130d85768f89bc2 (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
|
/*-------------------------------------------------------------------------
*
* pg_iovec.h
* Header for vectored I/O functions, to use in place of <sys/uio.h>.
*
* Portions Copyright (c) 1996-2023, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
* src/include/port/pg_iovec.h
*
*-------------------------------------------------------------------------
*/
#ifndef PG_IOVEC_H
#define PG_IOVEC_H
#ifndef WIN32
#include <limits.h>
#include <sys/uio.h>
#else
/* POSIX requires at least 16 as a maximum iovcnt. */
#define IOV_MAX 16
/* Define our own POSIX-compatible iovec struct. */
struct iovec
{
void *iov_base;
size_t iov_len;
};
#endif
/* Define a reasonable maximum that is safe to use on the stack. */
#define PG_IOV_MAX Min(IOV_MAX, 32)
/*
* Note that pg_preadv and pg_pwritev have a pg_ prefix as a warning that the
* Windows implementations have the side-effect of changing the file position.
*/
#if HAVE_DECL_PREADV
#define pg_preadv preadv
#else
extern ssize_t pg_preadv(int fd, const struct iovec *iov, int iovcnt, off_t offset);
#endif
#if HAVE_DECL_PWRITEV
#define pg_pwritev pwritev
#else
extern ssize_t pg_pwritev(int fd, const struct iovec *iov, int iovcnt, off_t offset);
#endif
#endif /* PG_IOVEC_H */
|
