Strdup

Hello!

Im trying to make work this function that works like the real strdup() function but i get
"error: invalid conversion from `void*' to `char*'" on the return; line.

Code:

---

#include <iostream>
using namespace std;

char * strdup(const char * s)
{
    size_t len = 1+strlen(s);
    char *p = (char*)malloc(len);

    return p ? memcpy(p, s, len) : NULL; // error here
}

int main(int nArg, char* pszArgs[])
{
    char buf[6] = "hello";

    cout << strdup(buf) << endl;
}

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If you're using iostream, then I guess you really are writing in C++. C++ has no conversion from void* to char*, unless you explicitly do so with a cast.

Thanks Tabstop but i dont see why is it talking about void* to char* conversion when p* and s* are both of type char*.

Edit: ok i see that its memcopy() that takes void* parameters, so i guess i should use another function.

The return type of memcpy is void*. That is what your last line attempts to return, hence the error. If you want that to compile:

Code:

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return p ? reinterpret_cast<char*>(memcpy(p, s, len)) : NULL;

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Quote:

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Originally Posted by Ducky

Hello!

Im trying to make work this function that works like the real strdup() function but i get
"error: invalid conversion from `void*' to `char*'" on the return; line.

Code:

---

#include <iostream>
using namespace std;

char * strdup(const char * s)
{
    size_t len = 1+strlen(s);
    char *p = (char*)malloc(len);

    return p ? memcpy(p, s, len) : NULL; // error here
}

int main(int nArg, char* pszArgs[])
{
    char buf[6] = "hello";

    cout << strdup(buf) << endl;
}

---

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You're using bad C programming practices to write C++ programs. Use an std::string and be done with it...