C++ getenv() wrapper function not setting the value - c++

Question

The cplusplus.com documentation on getenv() states...
The pointer returned points to an internal memory block, whose content or validity may be altered by further calls to getenv
...which I take to mean, "If you want to keep the content, copy it." So, since I need to retrieve several variables, I wrote a couple of little wrapper functions:
#include <iostream>
#include <string.h>
using namespace std;
void getEnv (char *val, const char *var) {
val = nullptr;
char *enVar = getenv(var);
if (enVar != nullptr) {
val = new char[strlen(enVar) + 1];
strcpy(val, enVar);
}
}
void getEnv (int &val, const char *var) {
val = -1;
char *enVar = getenv(var);
if (enVar != nullptr) {
val = atoi(enVar);
}
}
int main() {
char *textMode = nullptr;
int cLen = 0;
getEnv(cLen, "CONTENT_LENGTH");
cout << cLen << endl << endl;
getEnv(textMode, "TEXT_MODE");
if (textMode == nullptr)
cout << "Not set.";
else
cout << "[" << textMode << "]<br>\n";
return 0;
}
The int version works as expected, but I get nothing back from the char version, and I mean nothing: if I don't initialize *textMode at declaration it remains an uninitialized pointer.
It's pointers, right? Right? I know it is. Gotta be pointers. I'll figure them out one of these days, but hey -- at least I got my linked list to work! Yay!

Answer 1

Your second function takes val (an int) by reference: void getEnv (int &val, const char *var) and so can modify the variable passed to it as you expect.
Your first function takes val (a char*) by value: void getEnv (char *val, const char *var) so modifying val has no affect on the variable passed to it. A simple solution is to simply take it as a reference as well: void getEnv (char *&val, const char *var)

Answer 2

Follow up to my comments and the OP's response to them.
Here's what I was thinking:
#include <iostream>
#include <string.h>
using namespace std;
// Use a class to encapsulate the data need to be captured
// in an environment variable.
class EnvironmentVariable
{
public:
EnvironmentVariable(char const* name) : name_(name), isSet_(false)
{
char *val = getenv(name);
if ( val != nullptr )
{
isSet_ = true;
this->value_ = val;
}
}
bool isSet() const
{
return isSet_;
}
void getValue(char const*& val) const
{
if ( isSet_ )
{
val = this->value_.c_str();
}
else
{
val = nullptr;
}
}
void getValue(int& val) const
{
if ( isSet_ )
{
val = stoi(this->value_);
}
else
{
val = 0; // Find a suitable default value
}
}
private:
std::string name_;
std::string value_;
bool isSet_;
};
int main() {
char const* textMode = nullptr;
int cLen = 0;
EnvironmentVariable env1("CONTENT_LENGTH");
env1.getValue(cLen);
cout << cLen << endl << endl;
EnvironmentVariable env2("TEXT_MODE");
env2.getValue(textMode);
if (textMode == nullptr)
cout << "Not set.\n";
else
cout << "[" << textMode << "]<br>\n";
return 0;
}