28 Jul 2012, 04:50

Dennis Lambe (6 posts)

When I compile @unity_fixture.c@ with gcc 4.4.3 and @-O0@, it compiles cleanly. However, when I compile it with @-O1@ or greater, I get the following warning:

gcc -IUnity/src -IUnity/extras/fixture/src -O1 -c Unity/extras/fixture/src/unity_fixture.c -o test/build/unity_fixture.o
Unity/extras/fixture/src/unity_fixture.c: In function ‘unity_malloc’:
Unity/extras/fixture/src/unity_fixture.c:202: warning: incompatible implicit declaration of built-in function ‘malloc'

@unity_fixture.c@ includes @@ before any reference to @malloc@, so I can't see why this would be happening, let alone only happening at some optimization levels.

It’s causing trouble for me because I’d like to use @-Werror@ on my builds.

21 Dec 2012, 20:37

Dennis Lambe (6 posts)

I’ve tracked this bug down. The short answer is, @unity_fixture.c@ should include @string.h@ before unity_fixture.h.

It seems that @string.h@ on Linux may include a minimal @stdlib.h@ which includes definitions for malloc and calloc (see @bits/string2.h@ and the macro @__need_malloc_and_calloc@).

Since @unity_fixture.h@ is included in @unity_fixture.c@ before @string.h@, a preprocessor definition of @malloc@ -> @unity_malloc@ exists when @string.h@ includes @stdlib.h@, and @stdlib.h@ accidentally emits a prototype for a function named @unity_malloc@ instead of one named malloc. @stdlib.h@ also sets @__malloc_and_calloc_defined@ so that it doesn’t try to define those functions twice, so the later explicit including of @stdlib.h@ doesn’t get us the @malloc@ and @calloc@ prototypes we want.


09 Jan 2013, 17:47

Dennis Lambe (6 posts)

I got the fix for this bug merged upstream. Details here:


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