malloc error: a value of type "void *" cannot be used to initialize an entity of type "int **"

Question

I have tried:

int** thread_args = malloc(24);

and

int** thread_args = malloc(sizeof(int*) * 3);

but I keep getting the error message.

I would really appreciate your help!

Solution

If you use C++ compiler, you may need to cast the result of malloc:

int ** th_args = (int**)malloc(24)

or simply use operator new.

If you use a C compiler, then... I am not sure of why this error is thrown

Comments

[tkausl]

Are you compiling with a C++ compiler?

[Gaurav Pathak]

Possible duplicate of invalid conversion from *void to *int [-fpermissive] using malloc(sizeof())

[CottonCandy]

@tkausl yes. I am new to C++, and I never used to get this error in C99

[Gaurav]

@Isaacmalloc is C specific. use new in CPP.

[tkausl]

Well you should tag C++ then, not C. This is valid in C but not in C++. You have to decide which language you want to program in.

[melpomene]

Possible duplicate of Why does C++ require a cast for malloc() but C doesn't?

[HostileFork says dont trust SE]

@Isaac See Wikipedia article Compatibility of C and C++

[M.M]

You should not use malloc in C++

[molbdnilo]

You forgot to try int** thread_args = new int*[3];, which is the C++ way. Next stop on the C++ train: std::vector<std::vector<int>> thread_args(3);.

[melpomene]

I'm pretty sure you're supposed to use static_cast<> in C++ (or an existing container type, really).