CODEWITHSUNDEEP
c++
MTV
MTV

Reputation: 159

"Undefined Reference" error to a function I've already declared and defined and #included

I've created a header file reachability.h and a source reachability.cc in which I've declared a function map_nodes(). However, I can't compile due to the error: 

g++ -g lab1.o parser.o gate.o -o run
lab1.o: In function `main':
/home/ubuntu/workspace/ECE597/Lab1/lab1.cc:24: undefined reference to `map_nodes(std::vector<gate*, std::allocator<gate*> >)'
collect2: error: ld returned 1 exit status
make: *** [all] Error 1

I double checked declarations of data structure that is passed to map_nodes() and they are in the right place so that isn't the problem. I checked to #include "reachability.h" in main and that's done. I also checked the parameter type and they match.

I can't figure out why the function isn't visible.

Here is an image of my workspace:

ide-undef-err.png

Upvotes: 0

Views: 54

Answers (2)

MikeCAT
MikeCAT

Reputation: 75062

You didn't link reachability.cc, where the function is defined. Link it to solve this probrem.

Example:

$ g++ -c reachability.cc
$ g++ -g lab1.o parser.o gate.o reachability.o -o run

($ is a prompt and you shouldn't enter it)

Upvotes: 0

R Samuel Klatchko
R Samuel Klatchko

Reputation: 76611

Asssuming reachability.cc was compiled to reachability.o, you need to link with it as well:

g++ -g lab1.o parser.o gate.o reachability.o -o run

Upvotes: 1

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