On Mon, 28 Apr 2008, Erland Sommarskog wrote:
>
> I have this piece of code in my XS module:
>
> if (sv = get_sv("Win32::SqlServer::Version", TRUE))
> {
> char buff[256];
> sprintf_s(buff, 256,
> "This is Win32::SqlServer, version %s\n\nCopyright (c)
> 2005-2008 Erland Sommarskog\n",
> XS_VERSION);
> sv_setnv(sv, atof(XS_VERSION));
> sv_setpv(sv, buff);
> SvNOK_on(sv);
> }
>
> In Perl 5.10 this yields:
>
> Name "Win32::SqlServer::Version" used only once: possible typo at
> F:/Perl/AS1002-AMD64/lib/DynaLoader.pm line 224.
>
> Indeed, this variable is not referred elsewhere, but this did not happen in
> Perl 5.8.
>
> Is this an incidental or accidental change?
You were always supposed to get the warning; that you got away without
one is a bug. :)
> The workaround seems to be to add a reference in the PM module, although
> I have not come around to try that yet. Or should I do the above in some
> better way?
Use the GV_ADDMULTI flag:
if (sv = get_sv("Win32::SqlServer::Version", TRUE | GV_ADDMULTI))
Look it up in perlguts.pod:
| =head2 Creating New Variables
|
| To create a new Perl variable with an undef value which can be accessed from
| your Perl script, use the following routines, depending on the variable type.
|
| SV* get_sv("package::varname", TRUE);
| AV* get_av("package::varname", TRUE);
| HV* get_hv("package::varname", TRUE);
|
| Notice the use of TRUE as the second parameter. The new variable can now
| be set, using the routines appropriate to the data type.
|
| There are additional macros whose values may be bitwise OR'ed with the
| C<TRUE> argument to enable certain extra features. Those bits are:
|
| =over
|
| =item GV_ADDMULTI
|
| Marks the variable as multiply defined, thus preventing the:
|
| Name <varname> used only once: possible typo warning.
|
| =item GV_ADDWARN
|
| Issues the warning:
|
| Had to create <varname> unexpectedly
|
| if the variable did not exist before the function was called.
|
| =back
Cheers,
-Jan
