undefined reference to 'crypt'

{\rtf1\ansi\ansicpg1252\deff0\deflang1033{\fonttbl {\f0\fswiss\fcharset0 Arial;}}
\uc1\pard\ulnone\f0\fs20 Hello,\par
\par
After successfully installed the postgresql onto RedHat Linux 6.0,\par
I ran into the following error while compiling the example c++ programs\par
with libpq++ in ~/interfaces/libpq++/examples directory:\par
\tab libpq.so.2.0: undefined reference to 'crypt'\par
\par
Any way to get around this?\par
Thanks in advance.\par
\par
alan\par
\par
}