FormatDateTime exceptions

[RobA]

Hi all,

I'm a bit puzzled by FormatDateTime and EConvertError. According to the docs:

"FormatDateTime formats the date and time encoded in DateTime according to the formatting given in FormatStr. The complete list of formatting characters can be found in formatchars."

and:

"On error (such as an invalid character in the formatting string), and EConvertError exception is raised."

Based on that, I assumed that if FormatStr contained characters not listed in formatchars, and not a literal, then it would raise an exception. Indeed,

Code: Pascal  [Select][+][-]

1. try
2.     writeln('Test: '+formatdatetime('a',Now));
3.   except
4.     on E:EConvertError do
5.       writeln(E.Message);
6.   end;

does exactly that. But

Code: Pascal  [Select][+][-]

1. try
2.     writeln('Test: '+formatdatetime('b',Now));
3.   except
4.     on E:EConvertError do
5.       writeln(E.Message);
6.   end;

does not. Instead, it prints an upper case B to the console (it's a basic console program). Why does this happen, given that neither a nor b are listed in FormatChars? I was hoping to accept arbitrary format strings as command line parameters, and just pass them directly to FormatDateTime on the assumption that I could catch any invalid character via EConvertError, but it looks like I can't do that. Do I have to parse the user-supplied format strings myself?

TIA,

Rob

[Zvoni]

Because the "a" gets interpreted as an incomplete "12hours"-Formatstring, while the "b" gets interpreted as an literal

FormatDateTime calls DateTimeToString.
Look in dati.inc
C:\lazarus\fpc\3.2.2\source\rtl\objpas\sysutils\dati.inc
Beginning in Line 1014 (at least in my installation)

[RobA]

Ahhh, yes, I see now - thanks for that.

I had misunderstood the docs, assuming that literals had to be within quotes. Now I see that everything is treated as a literal unless it's a format char, and they need to be quoted if they're to be used as a literal.

Thanks again