Many OS/2 multimedia commands return strings. It is possible to check these strings against an expected value with an expected return string line.
An expected return string line has the format:
=result
The equal sign (=) must be in column 1 and should have no trailing spaces. If an empty string is expected, nothing should follow the = (not even spaces). For example:
status cdaudio ready wait =TRUE status cdaudio mode wait =stopped
The expected result is always interpreted as a string. This might produce some unusual outputs for commands that return binary data.
Where the return is a textual numerical value, it may be matched to a tolerance range of ±10% using a tilde (~) before the number. This is typically used when the exact value cannot be known. For example:
set foo time format milliseconds wait play foo notify @PAUSE 1000 stop foo wait status foo position wait =~1000
Thus, the status command is considered successful if the returned string is in the range 900 - 1100.