— Function: char* listserv_command (struct listserv *l, const char *command);

Sends command to listserv and returns the result. Errors in the communication protocol are reported to stderr. When there is an error, listserv_command returns a char* with '0' as first character. Example:

          char *ret = listserv_command (l, "SHOW VERSION");
          if (ret[0] == '0') printf ("listserv_command failed");