How do I use g++ to create object file with a specific name

Question

I am making a makefile and one of the targets is exptrtest.o how do I use g++ to create an objectfile with that name, the name of my cpp file is exprtest.cpp not exptrtest.cpp?

exptrtest.o: exprtest.cpp
    g++ -Wall -g -c exprtest.cpp

to make it more clear, this is my makefile:

all: exprtest
exprtest: exptrtest.o driver.o parser.tab.o scanner.o
    g++ -Wall -g -o exprtest exptrtest.o driver.o parser.tab.o scanner.o
exptrtest.o: exprtest.cpp
    g++ -Wall -g -c exptrtest.o exprtest.cpp
driver.o: driver.cpp scanner.hpp driver.hpp
    g++ -Wall -g -c driver.cpp
parser.tab.o: parser.tab.hpp parser.tab.cpp
    bison parser.ypp
    g++ -Wall -g -c parser.tab.cpp
scanner.o: scanner.cpp scanner.hpp
    flex -t scanner.ll > scanner.cpp
    g++ -Wall -g -c scanner.cpp
clean:
    rm parser.tab.hpp parser.tab.cpp scanner.cpp

I'm getting the error: "g++: error: exptrtest.o: No such file or directory make: * [exprtest] Error 1"

Solution

Use the -o option in conjunction with -c.

exptrtest.o: exprtest.cpp
    g++ -Wall -g -c exprtest.cpp -o exptrtest.o

Comments

[Trevor Hickey]

"g++ -c name.cpp" will create name.o. Use the -o flag to create a different output name.