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2
Definitions
1 Introduction
PHD API Reference
Crank Storyboard
Engine The runtime component that runs on the target device and presents the
content developed in Crank Storyboard Designer.
Crank Storyboard IO or
Storyboard IO This is a library and API provided by Crank Software that allows other
processes to send events to, and receive events from, the Crank Storyboard
Engine, or any other process using the Crank Storyboard IO library. Crank
Storyboard IO was previously known as, and often still referred to as
"greio". Every Crank Storyboard IO process creates a named channel for
listening and can send events to named channels created by other Crank
Storyboard IO processes.
DCP Dynamic Communications Platform
This is an API that abstracts a platform or OS-specific IPC protocol. It is
the IPC mechanism via which all of the Parker middleware communicates.
It is also the method by which system data is converted into Crank
Storyboard IO events for use by the user application.
Event An identifier used by the Storyboard IO library and the Storyboard Engine
to trigger an action. Events contain an event name and an event payload.
Event payload A blob of data associated with an event. The event payload is described
using a format string.
Format string Provides a description of how to interpret an event payload. The format
string uses the format:
[number of bytes][signed/unsigned][number of elements][ ] [name]
For example, standard C data types would be formatted as follows:
1s0 --> Special null terminated string
1s1|1u1 --> 1 byte integer (int8_t uint8_t)
2s1|2u1 --> 2 byte integer (int16_t uint16_t)
4s1|4u1 --> 4 byte integer (int32_t uint32_t)
4f1 --> 4 byte floating point (IEEE754 float)
8s1|8u1 --> 8 byte integer (int64_t uint64_t)
So a structure such as:
struct {
int32_t itemA;
uint16_t itemB;
}
would have the format string: 4s1 itemA 2u1 itemB .
When using numeric values, this API has, where ever possible, adopted a
32-bit signed or unsigned value. This is because ARM processors are more
efficient when using 32-bit quantities than other data sizes.
GPL The GNU General Public License, the license under which Linux kernel
source code and ancillary GPL utilities are released.
IPC Inter-Process Communications. A mechanism for moving a data between
two (or more) processes that may reside in separate address spaces.