Re: undefined reference, plz help

[Jonathan Wakely <jwakely dot gcc at gmail dot com>]

On 10 June 2011 02:20, Pavel Tolkachev wrote:
> --- On Thu, 6/9/11, Brian Budge <brian.budge@gmail.com> wrote:
>
>> From: Brian Budge <brian.budge@gmail.com>
>> Subject: Re: undefined reference, plz help
>> To: "eric lin" <ericlin@fsshl.zzn.com>
>> Cc: gcc-help@gcc.gnu.org
>> Date: Thursday, June 9, 2011, 8:52 AM
>> On Wed, Jun 8, 2011 at 9:26 PM, eric
>> lin <ericlin@fsshl.zzn.com>
>> wrote:
>> >
>> > Dear gcc programers:
>> >
>> > ?what may cause compile error (on 4.5.2 or maybe
>> not)
>> > ------
>> > ?g++ pg49.cpp
>> > /tmp/ccUvNoPf.o: In function `main':
>> > pg49.cpp:(.text+0x42): undefined reference to
>> `IntArray::IntArray(int*, int)'
>> > pg49.cpp:(.text+0x5e): undefined reference to
>> `IntArrayRC::IntArrayRC(int*, int)'
>> > /tmp/ccUvNoPf.o: In function `IntArray::~IntArray()':
>> >
>> pg49.cpp:(.text._ZN8IntArrayD2Ev[_ZN8IntArrayD5Ev]+0xb):
>> undefined reference to `vtable for IntArray'
>> > /tmp/ccUvNoPf.o: In function
>> `IntArrayRC::~IntArrayRC()':
>> >
>> pg49.cpp:(.text._ZN10IntArrayRCD2Ev[_ZN10IntArrayRCD5Ev]+0xb):
>> undefined reference to `vtable for IntArrayRC'
>> > collect2: ld returned 1 exit status
>> > --------
>> > eric ?/* I am happy to supply code I compiled, plz
>> show up your private email address or email me privately */
>> >
>> >
>> >
>> >
>>
>> This means that you've declared, but not defined those
>> constructors.
>> At link time, the linker cannot find the code for those
>> functions.
>>
>> ? Brian
>>
> Just a small correction: these are destructors or other virtual functions that are undefined, not constructors.

Actually it's both.