Problem of using malloc() without including stdlib.h

[Alan Bateman]

On 18/01/2012 08:19, Jonathan Lu wrote:
> Hi core-libs-dev,
>
> I found that for some native code of OpenJDK code base, malloc() is 
> used without including header file stdlib.h, such as following files,
> ./src/solaris/native/sun/java2d/opengl/GLXSurfaceData.c
> ./src/solaris/native/sun/java2d/x11/XRBackendNative.c
> ....
>
> I assume that there's no hacking tricks involved here, right? because 
> this may cause problem for some C compilers, which assumes 'int' as 
> the default return type of a function if it cannot find the function's 
> declaration during compiling. Under such a condition, actual return 
> result of type 'void*' from malloc() will be converted to 'int', which 
> may result in truncated pointers in 64bit platforms. If the 
> application tries to dereference such a broken pointer, error will occur.
>
> Indeed I found some indirect includes of stdlib.h, but there're still 
> some I do not see a stdlib.h get included from any of  the 
> direct/indirect included headers. I think in order to fix this 
> problem, two approaches may be considered here,
> a) add "#include <stdlib.h>" to every missing .c file.
> b) add "#include <stdlib.h>" to a commonly  referenced header file, 
> such as jni_util.h. but it would not be easy to find such a file for 
> all and creating one is the same as approach a).
>
> But both methods need to change many files, any other ideas about how 
> to fix it more elegantly?
>
> Thanks and best regards!
> - Jonathan
>
I would suggest bringing this up on the 2d-dev list so that the folks 
that maintain this area can help.

-Alan.