How to get rid of `deprecated conversion from string constant to ‘char*’` warnings in GCC?
Any functions into which you pass string literals "I am a string literal"
should use char const *
as the type instead of char*
.
If you're going to fix something, fix it right.
Explanation:
You can not use string literals to initialise strings that will be modified, because they are of type const char*
. Casting away the constness to later modify them is undefined behaviour, so you have to copy your const char*
strings char
by char
into dynamically allocated char*
strings in order to modify them.
Example:
#include <iostream>
void print(char* ch);
void print(const char* ch) {
std::cout<<ch;
}
int main() {
print("Hello");
return 0;
}
I believe passing -Wno-write-strings
to gcc will suppress this warning.
I had a similar problem, I solved it like this:
#include <string.h>
extern void foo(char* m);
int main() {
// warning: deprecated conversion from string constant to ‘char*’
//foo("Hello");
// no more warning
char msg[] = "Hello";
foo(msg);
}
Is this an appropriate way of solving this? I do not have access to foo
to adapt it to accept const char*
, although that would be a better solution (because foo
does not change m
).