AT command list as char * array - c++

Question

,,I need to provide an AT command to a modem which looks like this: AT^SRPN=1,99991,"Download_URL","Image";^SMSO
How can I insert the variable download_url and the variable image into the commands string array? Is the right way to declare the commands array not as const and to use strcpy() to insert the two variables into the commands list?
The function at_send_commands() needs the commands list as const.
Function proto: at_resp_t at_send_commands(TickType ticks_to_wait, const char *commands[]);
at_resp_t at_send_download_url_and_image(const char *download_url, const char *image)
{
static const char *commands[] =
{
"AT^SRPN=1,99991,",
download_url,
",",
image,
";^SMSO\r",
NULL
};
at_resp_t err = at_send_commands(AT_TIMEOUT, commands);
if (err)
return err;
}

Answer 1

Try this:
at_resp_t at_send_download_url_and_image(const char *download_url, const char *image)
{
std::string str("AT^SRPN=1,99991,");
str += download_url;
str += ",";
str += image;
str += ";^SMSO\r";
const char* command = str.c_str();
const char* commands[] =
{
command,
NULL
};
at_resp_t err = at_send_commands(AT_TIMEOUT, commands);
if (err)
return err;
}

Answer 2

In C the simplest way is IMO
void send_command(const char *download_url, const char *image) {
char buf[1000];
sprintf(buf, "AT^SRPN=1,99991,\"%s\",\"%s\";^SMSO",
download_url, image);
...
}
in buf you will end up having the final command to send to the modem.
If this code can be used in an hostile environment then you should also pay attention that no overflow can happen when passed large strings as url/image (e.g. add a check on strlen first or use snprintf instead).