Re: return values from a function call


Janis Papanagnou wrote:
paintedjazz@xxxxxxxxx wrote:
If I use the result of a function call in a condtional statement,
is it possible to return one of three possible values or is it just
true or false or a 0 or 1 status?

I want to test if a number is greater than, equal to or less than
another number.
Thus, the function should be something like:

if myfunction $num $another_num # return value is probably only 0 or
1
then
echo $num is greater than
else
echo $num is less than
fi

But I need to know if $num and $another_num are equal too.

Can I just have the function return a value (other than the status)
that could be tested?
How could I do that? Thx for your help.


You could of course return values of 0, 1, and 2 from the function,
then test the return code through variable $? in a case statement.

fn() { ...
return $anyresult
}

case $? in
...
esac

But the intention of the exit code is rather to indicate success
(code 0) or failure (code >0), and conceptually the shell functions
are more like commands than like mathematical functions. Values from
functions are usually returned through the "print interface"...

fn() { ...
print $anyresult
}

result=$( fn arg1 arg2 )
if [ $result -eq ... ]

Or use a case statement...

case $( fn arg1 arg2 ) in
...
esac


Janis

I'm not sure what the"print interface" is. Do you mean you just echo
or printf a string to stdout and that will end up as the result of the
function? I do like this way of doing it though.

.

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