Defines a broad set of APIs that allow the client application to query build and runtime properties of the enclosing system.
Runtime capabilities are boolean properties of a platform that can't be determined at compile-time. They may vary from device to device, but they will not change over the course of a single execution. They often specify particular behavior of other APIs within the bounds of their operating range.
Whether this system has reversed Enter and Back keys.
Whether this system has the ability to report on GPU memory usage. If (and only if) a system has this capability will SbSystemGetTotalGPUMemory() and SbSystemGetUsedGPUMemory() be valid to call.
Enumeration of device types.
Blue-ray Disc Player (BDP).
A relatively high-powered TV device used primarily for playing games.
Over the top (OTT) devices stream content via the Internet over another type of network, e.g. cable or satellite.
Set top boxes (STBs) stream content primarily over cable or satellite. Some STBs can also stream OTT content via the Internet.
A Smart TV is a TV that can directly run applications that stream OTT content via the Internet.
An Android TV Device.
A wall video projector.
Enumeration of special paths that the platform can define.
Path to where the local content files that ship with the binary are available.
Path to the directory that can be used as a local file cache, if available.
Path to the directory where debug output (e.g. logs, trace output, screenshots) can be written into.
Path to a directory where system font files can be found. Should only be specified on platforms that provide fonts usable by Starboard applications.
Path to a directory where system font configuration metadata can be found. May be the same directory as
kSbSystemPathFontDirectory, but not necessarily. Should only be specified on platforms that provide fonts usable by Starboard applications.
Path to a directory where temporary files can be written.
Full path to the executable file.
Path to a directory for permanent file storage. Both read and write access is required. This is where an app may store its persistent settings. The location should be user agnostic if possible.
Possible responses for
Enumeration of possible values for the
type parameter passed to the
Cobalt received a network connection error, or a network disconnection event. If the
response passed to
kSbSystemPlatformErrorResponsePositive then the request should be retried, otherwise the app should be stopped.
System properties that can be queried for. Many of these are used in User-Agent string generation.
The certification scope that identifies a group of devices.
The full model number of the main platform chipset, including any vendor- specific prefixes.
The production firmware version number which the device is currently running.
A friendly name for this actual device. It may include user-personalization like “Upstairs Bedroom.” It may be displayed to users as part of some kind of device selection (e.g. in-app DIAL).
A deprecated alias for
The name of the brand under which the device is being sold.
The final production model number of the device.
The year the device was launched, e.g. “2016”.
The corporate entity responsible for submitting the device to YouTube certification and for the device maintenance/updates.
The name of the operating system and platform, suitable for inclusion in a User-Agent, say.
The Google Speech API key. The platform manufacturer is responsible for registering a Google Speech API key for their products. In the API Console ( http://developers.google.com/console ), you can enable the Speech APIs and generate a Speech API key.
A field that, if available, is appended to the user agent
Advertising ID or IFA, typically a 128-bit UUID Please see https://iabtechlab.com/OTT-IFA for details. Corresponds to ‘ifa’ field. Note:
ifa_type ifa_type field is not provided.
Limit advertising tracking, treated as boolean. Set to nonzero to indicate a true value. Corresponds to ‘lmt’ field.
Pointer to a function to compare two items. The return value uses standard
< 0 if
a is less than
0 if the two items are equal
> 1 if
a is greater than
a: The first value to compare.
b: The second value to compare.
typedef int(* SbSystemComparator) (const void *a, const void *b)
A type that can represent a system error code across all Starboard platforms.
typedef int SbSystemError
Type of callback function that may be called in response to an error notification from
response is a code to indicate the user's response, e.g. if the platform raised a dialog to notify the user of the error.
user_data is the opaque pointer that was passed to the call to
typedef void(* SbSystemPlatformErrorCallback) (SbSystemPlatformErrorResponse response, void *user_data)
Breaks the current program into the debugger, if a debugger is attached. If a debugger is not attached, this function aborts the program.
SB_NORETURN void SbSystemBreakIntoDebugger()
Clears the last error set by a Starboard call in the current thread.
Returns the type of the device.
Generates a human-readable string for an error. The return value specifies the total desired length of the string.
error: The error for which a human-readable string is generated.
out_string: The generated string. This value may be null, and it is always terminated with a null byte.
string_length: The maximum length of the error string.
int SbSystemGetErrorString(SbSystemError error, char *out_string, int string_length)
Returns pointer to a constant global struct implementing the extension named
name, if it is implemented. Otherwise return NULL.
Extensions are used to implement behavior which is specific to the combination of application & platform. An extension relies on a header file in the “extension” subdirectory of an app, which is used by both the application and the Starboard platform to define an extension API struct. Since the header is used both above and below Starboard, it cannot include any files from above Starboard. It may depend on Starboard headers. That API struct has only 2 required fields which must be first: a const char*
name, storing the extension name, and a uint32_t
version storing the version number of the extension. All other fields may be C types (including custom structs) or function pointers. The application will query for the function by name using SbSystemGetExtension, and the platform returns a pointer to the singleton instance of the extension struct. The singleton struct should be constant after initialization, since the application may only get the extension once, meaning updated values would be ignored. As the version of extensions are incremented, fields may be added to the end of the struct, but never removed (only deprecated).
const void* SbSystemGetExtension(const char *name)
Gets the last platform-specific error code produced by any Starboard call in the current thread for diagnostic purposes. Semantic reactions to Starboard function call results should be modeled explicitly.
Gets the system's current POSIX-style Locale ID. The locale represents the location, language, and cultural conventions that the system wants to use, which affects which text is displayed to the user as well as how displayed numbers, dates, currency, and similar values are formatted.
At its simplest, the locale ID can just be a BCP 47 language code, like
en_US. Currently, POSIX also wants to include the encoding as in
en_US.UTF8. POSIX also allows a couple very bare-bones locales, like “C” or “POSIX”, but they are not supported here. POSIX also supports different locale settings for a few different purposes, but Starboard only exposes one locale at a time.
RFC 5646 describes BCP 47 language codes: https://tools.ietf.org/html/bcp47
For more information than you probably want about POSIX locales, see: http://pubs.opengroup.org/onlinepubs/9699919799/basedefs/V1_chap07.html
const char* SbSystemGetLocaleId()
Returns the number of processor cores available to this application. If the process is sandboxed to a subset of the physical cores, the function returns that sandboxed limit.
Retrieves the platform-defined system property specified by
property_id and places its value as a zero-terminated string into the user-allocated
out_value unless it is longer than
value_length - 1. This implementation must be thread- safe.
This function returns
true if the property is retrieved successfully. It returns
false under any of the following conditions and, in any such case,
out_value is not changed:
property_id is invalid for this platform
value_length is too short for the given result
out_value is NULL
property_id: The system path to be retrieved.
out_value: The platform- defined system property specified by
value_length: The length of the system property.
bool SbSystemGetProperty(SbSystemPropertyId property_id, char *out_value, int value_length)
A cryptographically secure random number generator that produces an arbitrary, non-negative number of
buffer_size random, non-negative bytes. The generated number is placed in
out_buffer. This function does not require manual seeding.
out_buffer: A pointer for the generated random number. This value must not be null.
buffer_size: The size of the random number, in bytes.
void SbSystemGetRandomData(void *out_buffer, int buffer_size)
A cryptographically secure random number generator that gets 64 random bits and returns them as an
uint64_t. This function does not require manual seeding.
Places up to
stack_size instruction pointer addresses of the current execution stack into
out_stack. The return value specifies the number of entries added.
The returned stack frames are in “downward” order from the calling frame toward the entry point of the thread. So, if all the stack frames do not fit, the ones truncated will be the less interesting ones toward the thread entry point.
This function is used in crash signal handlers and, therefore, it must be async- signal-safe on platforms that support signals. The following document discusses what it means to be async-signal-safe on POSIX: http://pubs.opengroup.org/onlinepubs/009695399/functions/xsh_chap02_04.html#tag_02_04_03
out_stack: A non-NULL array of
void * of at least
stack_size: The maximum number of instruction pointer addresses to be placed into
out_stack from the current execution stack.
int SbSystemGetStack(void **out_stack, int stack_size)
Returns the total CPU memory (in bytes) potentially available to this application. If the process is sandboxed to a maximum allowable limit, the function returns the lesser of the physical and sandbox limits.
Returns the total GPU memory (in bytes) available for use by this application. This function may only be called the return value for calls to SbSystemHasCapability(kSbSystemCapabilityCanQueryGPUMemoryStats) is
Returns the total physical CPU memory (in bytes) used by this application. This value should always be less than (or, in particularly exciting situations, equal to) SbSystemGetTotalCPUMemory().
Returns the current amount of GPU memory (in bytes) that is currently being used by this application. This function may only be called if the return value for calls to SbSystemHasCapability(kSbSystemCapabilityCanQueryGPUMemoryStats) is
Returns whether the platform has the runtime capability specified by
capability_id. Returns false for any unknown capabilities. This implementation must be thread-safe.
capability_id: The runtime capability to check.
bool SbSystemHasCapability(SbSystemCapabilityId capability_id)
Hides the system splash screen on systems that support a splash screen that is displayed while the application is loading. This function may be called from any thread and must be idempotent.
Attempts to determine whether the current program is running inside or attached to a debugger. The function returns
false if neither of those cases is true.
Returns if the device is disconnected from network. “Disconnected” is chosen over connected because disconnection can be determined with more certainty than connection usually.
Cobalt calls this function to notify the platform that an error has occurred in the application that the platform may need to handle. The platform is expected to then notify the user of the error and to provide a means for any required interaction, such as by showing a dialog.
The return value is a boolean. If the platform cannot respond to the error, then this function should return
false, otherwise it should return
This function may be called from any thread, and it is the platform's responsibility to decide how to handle an error received while a previous error is still pending. If that platform can only handle one error at a time, then it may queue the second error or ignore it by returning
type: An error type, from the SbSystemPlatformErrorType enum, that defines the error.
callback: A function that may be called by the platform to let the caller know that the user has reacted to the error.
user_data: An opaque pointer that the platform should pass as an argument to the callback function, if it is called.
bool SbSystemRaisePlatformError(SbSystemPlatformErrorType type, SbSystemPlatformErrorCallback callback, void *user_data)
Requests that the application move into the Blurred state at the next convenient point. This should roughly correspond to “unfocused application” in a traditional window manager, where the application may be partially visible.
This function eventually causes a
kSbEventTypeBlur event to be dispatched to the application. Before the
kSbEventTypeBlur event is dispatched, some work may continue to be done, and unrelated system events may be dispatched.
Requests that the application move into the Concealed state at the next convenient point. This should roughly correspond to “minimization” in a traditional window manager, where the application is no longer visible. However, the background tasks can still be running.
This function eventually causes a
kSbEventTypeConceal event to be dispatched to the application. Before the
kSbEventTypeConceal event is dispatched, some work may continue to be done, and unrelated system events may be dispatched.
In the Concealed state, the application will be invisible, but probably still be running background tasks. The expectation is that an external system event will bring the application out of the Concealed state.
Requests that the application move into the Started state at the next convenient point. This should roughly correspond to a “focused application” in a traditional window manager, where the application is fully visible and the primary receiver of input events.
This function eventually causes a
kSbEventTypeFocus event to be dispatched to the application. Before
kSbEventTypeFocus is dispatched, some work may continue to be done, and unrelated system events may be dispatched.
Requests that the application move into the Frozen state at the next convenient point.
This function eventually causes a
kSbEventTypeFreeze event to be dispatched to the application. Before the
kSbEventTypeSuspend event is dispatched, some work may continue to be done, and unrelated system events may be dispatched.
In the Frozen state, the application will be resident, but probably not running. The expectation is that an external system event will bring the application out of the Frozen state.
Requests that the application move into the Blurred state at the next convenient point. This should roughly correspond to a “focused application” in a traditional window manager, where the application is fully visible and the primary receiver of input events.
This function eventually causes a
kSbEventTypeReveal event to be dispatched to the application. Before the
kSbEventTypeReveal event is dispatched, some work may continue to be done, and unrelated system events may be dispatched.
Requests that the application be terminated gracefully at the next convenient point. In the meantime, some work may continue to be done, and unrelated system events may be dispatched. This function eventually causes a
kSbEventTypeStop event to be dispatched to the application. When the process finally terminates, it returns
error_level, if that has any meaning on the current platform.
error_level: An integer that serves as the return value for the process that is eventually terminated as a result of a call to this function.
void SbSystemRequestStop(int error_level)
Computes a HMAC-SHA256 digest of
digest using the application's certification secret.
The output will be written into
digest_size_in_bytes must be 32 (or greater), since 32-bytes will be written into it. Returns false in the case of an error, or if it is not implemented. In this case the contents of
digest will be undefined.
bool SbSystemSignWithCertificationSecretKey(const uint8_t *message, size_t message_size_in_bytes, uint8_t *digest, size_t digest_size_in_bytes)
Returns false if the platform doesn't need resume after suspend support. In such case Cobalt will free up the resource it retains for resume after suspend. Note that if this function returns false, the Starboard implementation cannot send kSbEventTypeResume to the event handler. The return value of this function cannot change over the life time of the application.
address as an instruction pointer and places up to (
buffer_size - 1) characters of the symbol associated with it in
out_buffer, which must not be NULL.
out_buffer will be NULL-terminated.
The return value indicates whether the function found a reasonable match for
address. If the return value is
out_buffer is not modified.
This function is used in crash signal handlers and, therefore, it must be async- signal-safe on platforms that support signals.
bool SbSystemSymbolize(const void *address, char *out_buffer, int buffer_size)