MessageBufferHandle_t xMessageBufferCreateStatic( size_t xBufferSizeBytes, uint8_t *pucMessageBufferStorageArea, StaticMessageBuffer_t *pxStaticMessageBuffer );
Creates a new message buffer using statically allocated memory. See xMessageBufferCreate() for a version that uses dynamically allocated memory.
xBufferSizeBytes | The size, in bytes, of the buffer pointed to by the pucMessageBufferStorageArea parameter. When a message is written to the message buffer an additional sizeof( size_t ) bytes are also written to store the message's length. sizeof( size_t ) is typically 4 bytes on a 32-bit architecture, so on most 32-bit architecture a 10 byte message will take up 14 bytes of message buffer space. The maximum number of bytes that can be stored in the message buffer is actually (xBufferSizeBytes - 1). |
pucMessageBufferStorageArea | Must point to a uint8_t array that is at least xBufferSizeBytes + 1 big. This is the array to which messages are copied when they are written to the message buffer. |
pxStaticMessageBuffer | Must point to a variable of type StaticMessageBuffer_t, which will be used to hold the message buffer's data structure. |
Example use:
// Used to dimension the array used to hold the messages. The available space // will actually be one less than this, so 999. #define STORAGE_SIZE_BYTES 1000
// Defines the memory that will actually hold the messages within the message // buffer. static uint8_t ucStorageBuffer[ STORAGE_SIZE_BYTES ];
// The variable used to hold the message buffer structure. StaticMessageBuffer_t xMessageBufferStruct;
void MyFunction( void ) { MessageBufferHandle_t xMessageBuffer;xMessageBuffer = xMessageBufferCreateStatic( sizeof( ucBufferStorage ), ucBufferStorage, &xMessageBufferStruct ); // As neither the pucMessageBufferStorageArea or pxStaticMessageBuffer // parameters were NULL, xMessageBuffer will not be NULL, and can be used to // reference the created message buffer in other message buffer API calls. // Other code that uses the message buffer can go here.}