Question on Aptitude search pattern

[Akhran]

I'm searching for a package called 'libstdc++2.10-glibc2.2'.
aptitude search libstdc++2.10-glibc2.2
or
aptitude search 'libstdc++2.10-glibc2.2'
or
aptitude search "libstdc++2.10-glibc2.2"
does not return me any result.

However, if I use
aptitude search libstdc.*2.10-glibc2.2
the package is found.

Any reason why the first three commands do not return the expected package?

Thanks !