Can I free the memory of the char* string when I assign it to std::string?

Question

Can I free the memory of the char* pointed string after I have convert it to a std::string? For example:

char* c_string; c_string = strdup("This is a test"); std::string cpp_string; cpp_string(c_string); free(c_string); /* can I call free here? */

@gongzhitaao Just because code compiles doesn't mean that it is correct. You could still be relying on undefined behavior. And std::string is perfectly valid in C++. You probably just forgot to include <string>. — Cody Gray
– Cody Gray ♦, Commented Apr 12, 2013 at 4:32
@It compiles and runs correctly. I suppose if it could not be freed then some runtime error will occure. What's more, What I mean is std:string instead of std::string. See the typo? — gongzhitaao
– gongzhitaao, Commented Apr 12, 2013 at 4:33

icktoofay · Accepted Answer · 2013-04-12 04:28:04Z

13

Yes. std::string copies the underlying C string.

^{Source: Table 67 of §21.4.2 of C++11 draft N3376.}

answered Apr 12, 2013 at 4:28

130k23 gold badges261 silver badges239 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

Jonathon Reinhart · Accepted Answer · 2013-04-12 04:28:18Z

Yes. The std::string constructor makes a copy of the string passed to it.

See constructor #4 on this page.

string (const char* s); // from c-string

from c-string

Copies the null-terminated character sequence (C-string) pointed by s.