Search code examples
c++castingstring-literals

Casting const char* to char* crashes

When I'm trying to cast const char* to char* it crashes:

int myfunc(const char*);
const char * str = "test";
myfunc( (char*)str ) // crash

How can I do that?

Solution

  • Update

    Attempting to modify a string literal is undefined behavior. If we look at the draft C++ standard section 2.14.5 String literals paragraph 12 says:

    Whether all string literals are distinct (that is, are stored in nonoverlapping objects) is implementation defined. The effect of attempting to modify a string literal is undefined.

    Crashing is one of many possible results of undefined behavior it is also possible to have a program that appears to work properly.

    Alternatively you can create a automatic array as follows:

    char str[] = "test" ;

    which will have a copy of the string literal which you can then modify.

    Original

    If myfunc is modifying a string literal then you have undefined behavior which can easily lead to your program crashing.