Compiling in Ubuntu 20.04.4 LTS, g++ returns
libpq-fe.h is not found
The system already has it installed (sudo apt-get install libpq-dev) in
/usr/include/postgresql/libpq-fe.h
I tried to set the compilation path with option -I/usr/include/postgresql but it still claims about missing libpq-fe.h
As you can see, I had to manually insert both -I/usr/include/postgresql and -L/usr/lib/x86_64-linux-gnu to make -lpq (libpq) work with g++ in Ubuntu:
TARGET = prog
LIBS = -lm -lcrypto -lpq -lpthread
CC = g++
CFLAGS = -g -Wall
ODIR = ../src
.PHONY: default all clean
default: $(TARGET)
all: default
OBJS = $(patsubst %.cpp, %.o, $(wildcard ../src/*.cpp))
HEADERS = $(wildcard ../src/*.h)
all: $(TARGET)
$(TARGET): $(OBJS)
$(CC) -L/usr/lib/x86_64-linux-gnu -o $@ $^ $(LIBS)
$(ODIR)/%.o: $(ODIR)/%.cpp
$(CC) $(CFLAGS) -I/usr/include/postgresql -c $< -o $@
clean:
-rm -f ../src/*.o
-rm -f $(TARGET)
In case of "cannot find -lpq" with libpq.so.5 already in /usr/lib/x86_64-linux-gnu:
sudo ln -s /usr/lib/x86_64-linux-gnu/libpq.so.5 /usr/lib/x86_64-linux-gnu/libpq.so