How to print binary content of bytes pointed by a pointer?

Question

I have a pointer returned from malloc. Which points to first byte of allocated size. For EX:

  void* p=malloc(34);

How to print the binary values contained in those 34 bytes. ?

Nothing of interest is contained in these bytes until you write to them. When malloc returns, the pointer points to garbage until you do some writes into that memory. — Sergey Kalinichenko, Mar 10 '14 at 10:38
@dasblinkenlight: I think markdown is affecting @vinod's comment, the italicised text runs right between where you'd expect two asterisks: `char *p = (char *) malloc()`... still, one shouldn't cast the result of malloc. — dreamlax, Mar 10 '14 at 10:54
Not sure he want really to print in binary, but rather "see" what's in that allocated memory. — Jabberwocky, Mar 10 '14 at 10:54

Jabberwocky · Accepted Answer · 2014-03-10T10:52:42.097

6

You probably want this :

int i ;
void* p=malloc(34);

for (i = 0; i < 34; i++)
{
  unsigned char c = ((char*)p)[i] ;
  printf ("%02x ", c) ;
}

It doesn't print in binary (010011011) but in hexadecimal, but that's probably what you want.

But as stated in the comments you will get garbage values.

edited Mar 10 '14 at 10:52

answered Mar 10 '14 at 10:46

Jabberwocky

1 Answers1