[C++] char * & a = char * b 이런 문법이 있나요?

#include <cstdlib>                                                             
#include <cstring>                                                             
#include <cstdio>                                                              
 
void strdup_with_reference(const char* in, char*& out) {                       
    size_t len = 0;                                                            
 
    if (in) {                                                                  
        len = strlen(in);                                                      
        out = new char[len];                                                   
    }                                                                          
 
    for(size_t i=0; i<len; i++) {                                              
        out[i] = in[i];                                                        
    }                                                                          
}                                                                              
 
void strdup_with_double_pointer(const char* in, char** out) {                  
    size_t len = 0;                                                            
 
    if (in) {                                                                  
        len = strlen(in);                                                      
        *out = new char[len];                                                  
    }                                                                          
 
    for(size_t i=0; i<len; i++) {                                              
        (*out)[i] = in[i];                                                     
    }                                                                          
}                                                                              
 
int main(int argc, char* argv[]) {                                             
    const char* in = "STRING";                                                 
    char* out1 = NULL;                                                         
    char* out2 = NULL;                                                         
 
    strdup_with_reference(in, out1);                                           
    strdup_with_double_pointer(in, &out2);                                     
 
    printf("%s\n", out1);                                                      
    printf("%s\n", out2);                                                      
 
    return EXIT_SUCCESS;                                                       
}