adb logcat 清空日志问题?

我用了adb logcat -c命令清空日志 在用adb logcat -d 还是输出之前的日志 日志没有被清空掉这么回事?

adb logcat -c
Usage: logcat [options] [filterspecs]
options include:
  -s              Set default filter to silent.
                  Like specifying filterspec '*:S'
  -f   Log to file. Default is stdout
  -r     Rotate log every kbytes. Requires -f
  -n      Sets max number of rotated logs to , default 4
  -v     Sets the log print format, where is:
                      brief color long printable process raw tag thread
                      threadtime time usec
  -D              print dividers between each log buffer
  -c              clear (flush) the entire log and exit