pg_iovec.h File Reference

#include <limits.h>

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Data Structures
struct	iovec

Macros
#define	IOV_MAX   16
#define	PG_IOV_MAX   Min(IOV_MAX, 32)

Functions
ssize_t	pg_preadv (int fd, const struct iovec *iov, int iovcnt, off_t offset)
ssize_t	pg_pwritev (int fd, const struct iovec *iov, int iovcnt, off_t offset)

Macro Definition Documentation

IOV_MAX

#define IOV_MAX   16

Definition at line 36 of file pg_iovec.h.

PG_IOV_MAX

#define PG_IOV_MAX   Min(IOV_MAX, 32)

Definition at line 40 of file pg_iovec.h.

Function Documentation

pg_preadv()

ssize_t pg_preadv	(	int	fd,
		const struct iovec *	iov,
		int	iovcnt,
		off_t	offset
	)

Definition at line 29 of file preadv.c.

References i, and pg_pread().

{
#ifdef HAVE_READV
    if (iovcnt == 1)
        return pg_pread(fd, iov[0].iov_base, iov[0].iov_len, offset);
    if (lseek(fd, offset, SEEK_SET) < 0)
        return -1;
    return readv(fd, iov, iovcnt);
#else
    ssize_t     sum = 0;
    ssize_t     part;

    for (int i = 0; i < iovcnt; ++i)
    {
        part = pg_pread(fd, iov[i].iov_base, iov[i].iov_len, offset);
        if (part < 0)
        {
            if (i == 0)
                return -1;
            else
                return sum;
        }
        sum += part;
        offset += part;
        if (part < iov[i].iov_len)
            return sum;
    }
    return sum;
#endif
}

pg_pwritev()

ssize_t pg_pwritev	(	int	fd,
		const struct iovec *	iov,
		int	iovcnt,
		off_t	offset
	)

Definition at line 29 of file pwritev.c.

References i, and pg_pwrite().

Referenced by pg_pwritev_with_retry().

{
#ifdef HAVE_WRITEV
    if (iovcnt == 1)
        return pg_pwrite(fd, iov[0].iov_base, iov[0].iov_len, offset);
    if (lseek(fd, offset, SEEK_SET) < 0)
        return -1;
    return writev(fd, iov, iovcnt);
#else
    ssize_t     sum = 0;
    ssize_t     part;

    for (int i = 0; i < iovcnt; ++i)
    {
        part = pg_pwrite(fd, iov[i].iov_base, iov[i].iov_len, offset);
        if (part < 0)
        {
            if (i == 0)
                return -1;
            else
                return sum;
        }
        sum += part;
        offset += part;
        if (part < iov[i].iov_len)
            return sum;
    }
    return sum;
#endif
}