This is my code snippet (the header file is trivial so not appear here).

#include<string>
#include<list>
#include<optional>
#include<malloc.h>

#include "include/common.h"
using std::list;
using std::string;
using std::optional;

optional<list<string>> split(string content, const char *delimiter) {

    char *buf = (char *)malloc(content.length());
    memcpy(buf, content.c_str(), content.length());

    const char *head = strtok(buf, delimiter);
    const char *foll = buf; // follow ptr
    list<string> l; 

    if(head == NULL){
        return std::nullopt;
    }

    while(head != nullptr) {
        DBG("%s", head);
        // DBG("%s", foll);
        // foll = head;
        head = strtok(NULL, delimiter);
    }

    
}
int main(){
    string s("123 12312 123213a as dasd as asd");
    split(s, " ");
}

and compile it with clang -o String String.cpp -g -std=c 17 -I../ -lstdc But it will crash when I execute it.

squ in