Geese
Hook Introduction
Many beginners (including me), when I start school, I am completely awkward, I don't know what it is. If you need to understand the HOOK function related configuration in this article, you need to understand what hook functions.
Hook function: hook translation means hook, hook, so it is called "hook function", you can understand what you want.
The hook function is actually a block of the operating system message processing mechanism, and it is hung into the system through system call.
The hook function can be said to be a function of operating system, like Windows, Linux, and UCOS embedded real-time operating systems that I have previously described in front of me have such hook functions.
The hook function is a function provided to the developer and implements something you want to implement. For example: The IDLE idle task in RTOS provides a hook function, I want to count it, count to 1W, I will print it out (that is, I want to implement what I want to implement).
In short, beginners do not have to fully master and master everything in the operating system, but must understand.
Thanks to the article I shared in the WeChat public number, you don't have to analyze or in depth. But it is necessary to understand, don't wait for the problem, then ask me to share the problems before you!
II
HOOK configuration
The above describes so much, I believe that everyone has a certain understanding of hook, below to describe the configuration in "freertosconfig.h".
1.configuse_idle_hook
Whether to define the IDLE idle task hook function
Configured to 0: Undefined
Configure 1: Definition
CONFIGUSE_IDLE_HOOK is the beginning of the system design and must be defined in "freertosconfig.h". Unlike some macro definitions may not be defined in "freertosconfig.h" because they have the default definition if they are defined in "freertos.h". If they are not defined, there is a default definition.
For example: The last article said "configuse_mutexes", can be defined in "freertosconfig.h", and you can see the following code in "Freertos.h":
#ifndef configuse_mutexes
#define configuse_mutexes 0
#ENDIF
That is, if it is not defined, it will default to you by default.
Let's come back, configuse_idle_hook, in the task.c file, there is the following code:
#if (configuse_idle_hook == 1)
{
Extern void vApplicationIdlehook (void);
vApplicationIdlehook ();
}
#ENDIF
It means: If you configure configuse_idle_hook 1, then you must implement "VAPPLICATIONIDEHOK ()" function, otherwise compiling will be wrong. The initiator does not default the function by default.
2.configuse_tick_hook
Whether to define Tick Tick Hook Functions
Configured to 0: Undefined
Configure 1: Definition
You can see the following code under the xtaskincrementTick function in the task.c file:
#if (configuse_tick_hook == 1)
{
IF (UxpendedTicks == (UbaseType_t) 0U)
{
VApplicationTickHook ();
}
Else
{
MTCOVERAGE_TEST_MARKER ();
}
}
#ENDIF
Tip: The XTaskIncremeTick function is called in the PENDSV_HANDLER interrupt function. Therefore, the time that the vApplication onTickhook () function executes must be short.
3.configcheck_for_stack_overflow
Whether defining stack overflow hook functions
Configured to 0: Undefined
Configure 1: Definition
This configuration is more important, especially for complex system design, the amount of code is relatively large, using this feature, you can help you analyze if there is a memory-proof.
4.configuse_malloc_failed_hook
Whether to define a memory allocation failure hook function
Configured to 0: Undefined
Configure 1: Definition
We create tasks, semaphors, queues, etc. need to spend system stack. If we are not enough to allocate stacks to the system, it is easy to assign a failure when creating multiple tasks or queues, and this time it plays a prompt.
5.configuse_daemon_task_startup_hook
Whether to define the daemon hook function
Configured to 0: Undefined
Configure 1: Definition
By analyzing the software source code, you can find that this hook function is implemented below the Timer Task, so you need to configuSE_timers 1. Read more
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