Re: strftime() using '-' to remove leading 0s functionality removed or broken?

[Ed Morton]

Apparently the person for whom the `-` works in gawk 4.2.1 also sees it 
working in gawk 5.3.0, see:

   https://imgur.com/a/YtgCkA6

They are testing on a Mac while I tested on 2 different laptops, both 
running Windows 11, one in cygwin and the other git bash, so I'm 
guessing this is something to do with underlying primitives. It's odd to 
me  that `date` behaves differently from `gawk` in this regard but I 
guess it's just implemented differently. FWIW perl behaves the same way 
as gawk:

   $ cat tst.prl
   #!/usr/bin/perl
   use POSIX qw(strftime);

   # Modules used
   use strict;
   use warnings;

   # Print function
   printf("Without -: %s\n", strftime "%m", localtime);
   printf("With -:%s\n", strftime "%-m", localtime);

   $ ./tst.prl
   Without -: 01
   With -:
   $

and so does python:

   $ cat tst.py
   #!/usr/bin/python
   from datetime import datetime

   now = datetime.now()

   print("Without -:", now.strftime("%m"))
   print("With -:", now.strftime("%-m"))

   $ ./tst.py
   Without -: 01
   With -:

Assuming it's not something that can/should be made to work portably, 
maybe it's worth a brief note in the documentation that this is a thing, 
just like the underlying primitives impact on rounding and reading 
binary files are described elsewhere in the docs?

    Ed.

On 1/27/2024 6:56 AM, Ed Morton wrote:
> Someone posted an answer at 
> https://stackoverflow.com/a/77884684/1745001 that puts a `-` in front 
> of `strftime()` format specifiers to remove leading `0`s so that, for 
> example, we can print the month number by doing:
>
>     awk 'BEGIN{print strftime("%-m")}'
>
> and get `1` output instead of the `01` we'd get with
>
>     awk 'BEGIN{print strftime("%m")}'
>
> That's consistent with how GNU date (and apparently various other 
> tools) works:
>
>     $ date +'%-m'
>     1
>     $
>
>     $ date +'%m'
>     01
>     $
>
> and it's what that SO answer shows with gawk 4.2.1.
>
> When I try to do the same with gawk 5.0.0 or later, though, then I get:
>
>     $ awk 'BEGIN{print strftime("%-m")}'
>
>     $
>
>     $ awk 'BEGIN{print strftime("%m")}'
>     01
>     $
>
> i.e. adding the `-` makes `strftime()` produce no output.
>
> That functionality isn't documented in the manual best I can tell - is 
> that functionality that was removed or is it breakage or something else?
>
>     Ed.