How to follow linking order when linking against static library with gnu-make?

Question

I've got the following problem: ``` cc -g -O2 -Wall -Wextra -Isrc -rdynamic -DNDEBUG build/liblcthw.a tests/list_tests.c -o tests/list_tests /tmp/ccpvGjZp.o: In function `test_create': ~/lcthw/tests/list_tests.c:12: undefined reference to `List_create' collect2: ld returned 1 exit status make: *** [tests/list_tests] Error 1 ``` But ``` cc -g -O2 -Wall -Wextra -Isrc -rdynamic -DNDEBUG tests/list_tests.c build/liblcthw.a -o tests/list_tests ``` runs just fine, `nm` shows the expected content, tests run, everybody is happy, etc. I've searched SO and found a plenty of answers (e.g. Linker order - GCC), so it's clear that linker works as it really should. So, how should I modify my makefile to follow the order? Here's the Makefile so far: ``` CFLAGS=-g -O2 -Wall -Wextra -Isrc -rdynamic -DNDEBUG $(OPTFLAGS) LIBS=$(OPTLIBS) PREFIX?=/usr/local BUILD=build SOURCES=$(wildcard src/**/*.c src/*.c) OBJECTS=$(patsubst %.c,%.o,$(SOURCES)) TEST_SRC=$(wildcard tests/*_tests.c) TESTS=$(patsubst %.c,%,$…

Accepted Answer

You don't show the makefile rule that is building `tests/list_tests` but it looks as though it's just the built-in rule. With GNU Make, you can print out that rule with `-p`, which will show you:

```
# default
LINK.c = $(CC) $(CFLAGS) $(CPPFLAGS) $(LDFLAGS) $(TARGET_ARCH)
[...]
.c:
#  recipe to execute (built-in):
    $(LINK.c) $^ $(LOADLIBES) $(LDLIBS) -o $@
```

By adding the library to `$(CFLAGS)` (via the target-specific variable `tests: CFLAGS+=$(TARGET)`), you are placing it before `$^` in the resulting command. Instead you should add it to `$(LDLIBS)` so that it appears after the object files:

```
tests: LDLIBS+=$(TARGET)
```

However note that relying on the propagation of target-specific variables like this doesn't work especially well in practice. When you type `make tests` then the library is used to build `tests/list_tests` et al. However when you are just interested in one test, you will find that `make tests/list_tests` fails because the link library is not included in the command. (See this answer for details.)

How to follow linking order when linking against static library with gnu-make?

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