Errno value from a process is higher than 128

Problem:

The command echo $?  Displays a value that is higher than 128. What does this value mean?

Resolution:

If the errno value that is displayed by the command echo $,  is higher than 128  ,  it means that the process was stopped by a signal = {Errno value} - 128

Example

Echo $?  displays 137  ,  the process was stopped by signal 9