xNetworkBufferDescriptor_t *pxNetworkBufferGet( size_t xRequestedSizeBytes,
TickType_t xBlockTimeTicks );
Obtains from the IP stack a free network buffer descriptor that (optionally) references a free Ethernet buffer.
pxNetworkBufferGet() must not be called from an interrupt service routine (ISR).
Parameters:
| xRequestedSizeBytes |
The size of the Ethernet buffer to obtain and reference
from the returned network buffer descriptor. The size
is specified in bytes.
If xRequestedSizeBytes is zero then the returned network buffer descriptor will not reference an Ethernet buffer (the reference is set to NULL).
|
| xBlockTimeTicks |
If a network buffer is not available then the calling task
will be held in the Blocked state (so other tasks can
execute) until either a network buffer becomes available
or the specified block time expires.
The block time is specified in RTOS ticks. To convert a time specified in milliseconds to a time specified in RTOS ticks divide the time specified in milliseconds by portTICK_PERIOD_MS.
|
Returns:
Successful calls return a pointer to the obtained network buffer descriptor. Unsuccessful calls return NULL.
Example usage:
Examples are provided on the Porting FreeRTOS to a Different Microcontroller page.