Question

What is the right way to convert long to char* const in C++?

EDIT:

long l = pthread_self();
ThirdPartyFunction("Thread_Id_"+l); //Need to do this


ThirdPartyFunction(char* const identifierString)
{}

Answer 1

EDIT:
The “proper” way to convert an integer to a string, in C++, is to use a stringstream. For instance:

#include <sstream>

std::ostringstream oss;
oss << "Thread_Id_" << l;
ThirdPartyFunction(oss.str().c_str());

Now, that probably won’t be the “fastest” way (streams have some overhead), but it’s simple, readable, and more importantly, safe.

---

OLD ANSWER BELOW

Depends on what you mean by “convert”.

To convert the long‘s contents to a pointer:

char * const p = reinterpret_cast<char * const>(your_long);

To “see” the long as an array of chars:

char * const p = reinterpret_cast<char * const>(&your_long);

To convert the long to a string:

std::ostringstream oss;
oss << your_long;
std::string str = oss.str();
// optionaly:
char * const p = str.c_str();