passing function pointer in c with a pointer argument

Question

Here, I have defined two function pointers func1 and func2, and I guess this a way to use function pointers in c.But my question is when I call

executor(func1);
executor(func2);

How can I allocate memory for uint8_t * and pass it as an argument for either func1 and func2, so that I can use it back in main()

typedef int (*FUNC_PTR)(uint64_t, uint8_t*);

void executor(FUNC_PTR func)
{ 
   uint64_t opts = 0x0000010;
   uint8_t val = 0;
   res = func(opts, &val);
}

int func1(uint64_t a, uint8_t* b)
{ 
   //do some stuff

}

int func2(uint64_t a, uint8_t* b)
{ 
//do some stuff
}

void main()
{
   executor(func1);
   executor(func2);
}

Your executor needs to take some extra argument(s) which will get passed to func and let the caller worry about the allocation.. Or use some global/static/dynamically allocated buffers. Which I would not recommend... — Eugene Sh.
– Eugene Sh., Commented Aug 21, 2018 at 21:21

merlin2011 · Accepted Answer · 2018-08-21 21:24:38Z

1

Just add it to the argument list of executor.

void executor(FUNC_PTR func, uint8_t* b)
{ 
   uint64_t opts = 0x0000010;
   res = func(opts, b);
}

You can allocate the memory on the stack or heap in main.

void main()
{
   uint8_t mem1, mem2;
   executor(func1, &mem1);
   executor(func2, &mem2);
}

answered Aug 21, 2018 at 21:24

merlin2011

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3 Comments

pavikirthi Over a year ago

Also, is there any way to just not pass any function, for example executor(void) something like that?

merlin2011 Over a year ago

@pavikirthi, I'm not sure I understand that question; I'd suggest asking a new question that specifies exactly what behavior you'd want if you passed in no arguments.

pavikirthi Over a year ago

Sure! Thank you

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