V675. Writing into the read-only memory.


The analyzer has detected an attempt of writing into read-only memory.

Have a look at the following sample:

char *s = "A_string";
if (x)
  s[0] = 'B';

The pointer 's' refers to a memory area which is read-only. Changing this area will cause undefined behavior of the program which will most probably take form of an access violation.

This is the fixed code:

char s[] = "A_string";
if (x)
  s[0] = 'B';

The 's' array is created on the stack, and a string from read-only memory is copied into it. Now you can safely change the 's' string.

P.S.

If "A_string" is "const char *", why should this type be implicitly cast to "char *"?

This is done due to compatibility reasons. There exists a TOO large amount of legacy code in C where non-constant pointers are used, and C++ standard/compiler developers didn't dare to break the backward compatibility with that code.

You can look at examples of errors detected by the V675 diagnostic.


Bugs Found

Checked Projects
355
Collected Errors
13 303