Print smallest integer from file using awk custom function?
 

`awk` function looks like this in a file name `fun.awk`:

The contents of `awk.write`:

The `awk` command is:

awk -f fun.awk awk.write

It gives me no result? Why?

Use a simpler program, e.g.
This assumes that the first field of each record is the number we check, and that all numbers are 0 or positive. It's not tested.

thanks for the one liner but can this code be translated to a function?

It would be rather different, clumsy and un-awk-ish. Why do you insist on a function?

And what is that function's specification - input and output?

Let me elaborate why I think a function is the wrong solution. awk programs consist of pattern-action pairs which work on one line at a time. Users can define functions for better structuring their actions.
Your task requires processing the entire file. While that is possible inside a single awk action, for instance using the built-in function getline, it's against awk's nature. It will also be hard to read compared to my two-line program.