Download AMX DESIGN XPRESS V 1.5 - PROGRAMMER GUIDE User`s guide

kvf_read
kvf_read
Purpose
Read from a Virtual File
Used by
n
Setup
Prototype is in file KN_FILES.H.
#include "KN_LIB.H"
#include "KN_FILES.H"
size_t kvf_read(void *buf, size_t size, size_t cnt,
KN_VFILE *vfd);
Description
Buf
Task
o
ISP
o
Timer Procedure
o
Restart Procedure
n
Exit Procedure
is a pointer to storage for the data items to be read from the file.
Size
is the size in bytes of each item which is to be read from the file.
Cnt
is the number of items to be read from the file.
Vfd
is a virtual file descriptor identifying an open virtual file to be read.
Note
For best efficiency when reading bytes from a file, set size to 1 and cnt
to the number of bytes to be read.
Returns
If successful, a value of n is returned where n is the number of full size
data items read from the file. The value n will be less than cnt if the end
of file is reached before cnt items of size bytes each can be read. The
virtual file pointer is incremented by the number of bytes actually read.
If size is 0 or cnt is 0, the value 0 is returned and the storage at *buf is
unaltered.
If parameter vfd does not reference an open virtual file and there is no
underlying file system to handle the request, a value of -1 is returned.
Note
If the parameter vfd does not reference a currently open virtual file, the
request is passed on via the KwikNet Universal File System Interface to the
underlying real file system, if one exists. In such a case, the return value
will be dictated by the equivalent fread() function.
See Also
kvf_close(), kvf_open()
KwikNet Virtual File System
KADAK
263