win32pread.c File Reference

#include "c.h"
#include <windows.h>

Include dependency graph for win32pread.c:

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

Function Documentation

pg_pread()

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

Definition at line 20 of file win32pread.c.

{
    OVERLAPPED  overlapped = {0};
    HANDLE      handle;
    DWORD       result;
 
    handle = (HANDLE) _get_osfhandle(fd);
    if (handle == INVALID_HANDLE_VALUE)
    {
        errno = EBADF;
        return -1;
    }
 
    /* Avoid overflowing DWORD. */
    size = Min(size, 1024 * 1024 * 1024);
 
    /* Note that this changes the file position, despite not using it. */
    overlapped.Offset = (DWORD) offset;
    overlapped.OffsetHigh = (DWORD) (offset >> 32);
 
    if (!ReadFile(handle, buf, size, &result, &overlapped))
    {
        if (GetLastError() == ERROR_HANDLE_EOF)
            return 0;
 
        _dosmaperr(GetLastError());
        return -1;
    }
 
    return result;
}

References _dosmaperr(), buf, fb(), fd(), and Min.