CODEWITHSUNDEEP
c++postgresql-9.1
Brent
Brent

Reputation: 21

C++ linking error when linking postgresql

When compiling my code I run into an issue as follows:

io.cpp:21: undefined reference to `PQconnectdb'

as well as all other instances of missing postgres function calls occurring in my code. Obviously this is a linking problem, I'm just not sure what the link issue is.

I'm compiling with the following:

mpiCC -c -O2 -g -Wall -Werror -I /usr/include/postgresql/ decisioning_mpi.cpp
g++ -c -O2 -g -Wall -Werror -I /usr/include/postgresql/ io.cpp
g++ -c -O2 -g -Wall -Werror -I /usr/include/postgresql/ calculations.cpp
g++ -c -O2 -g -Wall -Werror -I /usr/include/postgresql/ rules.cpp
g++ -c -O2 -g -Wall -Werror -I /usr/include/postgresql/ Instrument.cpp
g++ -c -O2 -g -Wall -Werror -I /usr/include/postgresql/ Backtest_Parameter_CPO.cpp
g++ -c -O2 -g -Wall -Werror -I /usr/include/postgresql/ Backtest_Trade_CPO.cpp
g++ -c -O2 -g -Wall -Werror -I /usr/include/postgresql/ Data_Bar.cpp
mpiCC -o decisioning_mpi -O2 -g -Wall -Werror -L/usr/lib -lm -lpq decisioning_mpi.o 
io.o calculations.o rules.o Instrument.o Backtest_Parameter_CPO.o Backtest_Trade_CPO.o Data_Bar.o

It should be noted that this is the correct directory for libpq-fe.h and that I'm linking pq, so I'm not exactly sure why the postgres functions aren't linking correctly. I'm running Ubuntu 12.04 and installed psql (PostgreSQL) 9.1.6 from synaptic. As well I'll short circuit this, I am using #include "libpq-fe.h".

Any ideas on how I can get this linking issue resolved?

Upvotes: 2

Views: 637

Answers (1)

billz
billz

Reputation: 45410

put -L/usr/lib/ -lm -lpq in the end of link command, the linker can then find the symbols

mpiCC -o decisioning_mpi -O2 -g -Wall -Werror decisioning_mpi.o io.o \
calculations.o rules.o Instrument.o Backtest_Parameter_CPO.o \
Backtest_Trade_CPO.o Data_Bar.o -L/usr/lib -lm -lpq

GCC Link Reference: http://www.network-theory.co.uk/docs/gccintro/gccintro_18.html

Upvotes: 1

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