SOL_OFS_PRINT_BUF_LEN
len += vsnprintf(msg_ptr, SOL_OFS_PRINT_BUF_LEN - len - 2, fmt, ap);
len = min(len, SOL_OFS_PRINT_BUF_LEN - 2);
static char sol_ofs_print_buf[SOL_OFS_PRINT_BUF_LEN];