On Saturday, 29 May 2021 at 02:26:57 UTC, someone wrote:
```d
core.stdc.stdio.printf("%'d", intAmount); /// Deprecation:
format specifier `"%'"` is invalid ... but it works: 1,234,567
as specified in my locale :)
```
D warns for format specifiers that do not conform to the C99
standard, and the `'` flag character is not part of C99. GCC
gives a similar warning with `-Wall -pedantic`:
```
$ gcc -Wall -pedantic -o example example.c
example.c: In function ‘main’:
example.c:5:9: warning: ISO C does not support the ''' printf
flag [-Wformat=]
printf("%'d\n", 123456789);
^~~~~~~
```
