Thank you very much. You are quite correct. An unbuffered file is ideal, and
yes, linux only (OpenWrt). Thank you for pointing me to the posix module (and
getFileHandle()). I am trying to decipher the most elegant way of accomplishing
this, but am failing miserably. this is what I have (UsbDevice.devicePaths[0]
is a string containing the path of the device file):
proc readDevice(dev: UsbDevice): DeviceReading =
let devfd = posix.open(dev.devicePaths[0], posix.O_RDWR)
# Close the file object when we are done with it
defer: discard posix.close(devfd)
#write trigger data to the device file
let writepack = [0x01'u8, 0x86'u8, 0xff'u8, 0x01'u8, 0'u8, 0'u8, 0'u8,
0'u8]
let written = posix.write(devfd, cast [ptr uint8](unsafeAddr(writepack)),
writepack.len)
#now read until there is no more data for 100ms
while true:
var selector = newSelector[int]() # I don't need user data, so is int
correct for T?
selector.registerHandle(cast[int](devfd), {Read}, 0)
var ready = selector.select(100)
echo(ready) # this is just to check that my selector is working.
break
#more code to come after the selector is working...........
Run
But it won't compile:
$ sudo nim c -r temper.nim
Hint: used config file '/etc/nim/nim.cfg' [Conf]
Hint: system [Processing]
Hint: temper [Processing]
Hint: strutils [Processing]
Hint: parseutils [Processing]
Hint: math [Processing]
Hint: bitops [Processing]
Hint: algorithm [Processing]
Hint: unicode [Processing]
Hint: sets [Processing]
Hint: hashes [Processing]
Hint: os [Processing]
Hint: times [Processing]
Hint: options [Processing]
Hint: typetraits [Processing]
Hint: strformat [Processing]
Hint: macros [Processing]
Hint: posix [Processing]
Hint: ospaths [Processing]
Hint: re [Processing]
Hint: pcre [Processing]
Hint: rtarrays [Processing]
Hint: tables [Processing]
Hint: selectors [Processing]
Hint: nativesockets [Processing]
Hint: epoll [Processing]
Hint: sequtils [Processing]
temper.nim(105, 25) template/generic instantiation from here
../../../../usr/lib/nim/pure/ioselects/ioselectors_epoll.nim(475, 25)
template/generic instantiation from here
../../../../usr/lib/nim/pure/ioselects/ioselectors_epoll.nim(390, 35)
Error: undeclared field: 'SockLen'
Run
