pread.c File Reference

#include "postgres.h"
#include <unistd.h>

Include dependency graph for pread.c:

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Functions
ssize_t	pg_pread (int fd, void *buf, size_t size, off_t offset)

Function Documentation

pg_pread()

ssize_t pg_pread	(	int	fd,
		void *	buf,
		size_t	size,
		off_t	offset
	)

Definition at line 27 of file pread.c.

References _dosmaperr(), and read.

Referenced by basebackup_read_file(), FileRead(), pg_preadv(), SlruPhysicalReadPage(), WALRead(), and XLogPageRead().

{
#ifdef WIN32
    OVERLAPPED  overlapped = {0};
    HANDLE      handle;
    DWORD       result;

    handle = (HANDLE) _get_osfhandle(fd);
    if (handle == INVALID_HANDLE_VALUE)
    {
        errno = EBADF;
        return -1;
    }

    overlapped.Offset = offset;
    if (!ReadFile(handle, buf, size, &result, &overlapped))
    {
        if (GetLastError() == ERROR_HANDLE_EOF)
            return 0;

        _dosmaperr(GetLastError());
        return -1;
    }

    return result;
#else
    if (lseek(fd, offset, SEEK_SET) < 0)
        return -1;

    return read(fd, buf, size);
#endif
}