SimGrid. Create subprocess with argument

Question

I have process declared in main.c:

MSG_function_register("dispatcher", dispatcher);

The dispatcher function gets arguments from deployment.xml file:

int num = xbt_str_parse_int(argv[1], "Invalid argument %s");
int id = xbt_str_parse_int(argv[2], "Invalid argument %s");

Then dispatcher creates a subprocess:

MSG_process_create_with_arguments("TS", subprocess, NULL, MSG_host_self(), agrc, argv);

How can I pass num and id to subprocess function?

int subprocess(int argc, char* argv){
    return 0;
}

How can I call this argv inside from subprocess function?

Answer 1

You have 2 ways to pass arguments to MSG processes:

• either via the argv;

• or via the data argument.

Pass the data via argv

In the first solution, you have to create a new argv:

// Create argv for child process
char** newargv = xbt_new(char*, 3);
newargv[1] = xbt_strdup("TS");
newargv[2] = xbt_strdup(argv[0]);
newargv[3] = xbt_strdup(argv[0]);
// Create process with new argv:
MSG_process_create_with_arguments("TS", subprocess, NULL,     MSG_host_self(), 3, newargv);

with:

int subprocess(int argc, char* argv)
{
    int num = xbt_str_parse_int(argv[1], "Invalid argument %s");
    int id = xbt_str_parse_int(argv[2], "Invalid argument %s");
    return 0;
}

Pass the data via data

Another solution is to pass the data using the data parameter:

struct ts_data {
  int num;
  int id;
};

struct ts_data* data = xbt_new(ts_data, 1);
data->num = xbt_str_parse_int(argv[1], "Invalid argument %s");
data->id = xbt_str_parse_int(argv[2], "Invalid argument %s");
MSG_process_create_with_arguments("TS", subprocess, data,     MSG_host_self(), 0, NULL

with:

int subprocess(int argc, char* argv)
{
    struct ts_data* data = MSG_process_get_data(MSG_process_self());
    int num = data->num;
    int id = data->id;
    free(data);
    return 0;
}