LibrariesinsideAPI reference

Updated May 2025

xApplicationGetRandomNumber()

[FreeRTOS-Plus-TCP API Reference]

FreeRTOS_sockets.h

1BaseType_t xApplicationGetRandomNumber( uint32_t * pulNumber );

xApplicationGetRandomNumber is an application defined hook (or callback) function that is called by the FreeRTOS-Plus-TCP stack to get a random number. Applications should strive to provide a true random number. If at all possible, a hardware random number generator should be used. The quality of provided random numbers greatly effects the security of communication.

Callback functions are implemented by the application writer, but called by the TCP/IP stack. The prototype of the callback function must exactly match the prototype above (including the function name). The code in an application hook should not call FreeRTOS-Plus-TCP API's that are blocking. That could easily lead to a dead-lock.

When an application hook executes, it borrows the task priority and the stack of the IP-task. Therefore, we recommend that you keep application hooks short--it may want to wakeup some application task which will do further processing.

Parameters:

  • pulNumber

    If the random number generation is successful, then this pointer is filled with the generated 32-bit random number.

Return value:

If the random number is successfully generated, then a pdTRUE should be returned and a copy of the random number in the pulNumber parameter should be made. Otherwise a pdFALSE should be returned.