FreeRTOS Hungarian Notation [duplicate]

问题

I'm a complete newbie in RTOS and C programming, and I'm still getting used to the C good practices yet. So I opened a project which uses FreeRTOS, and I notice that the OS files use the Hungarian Notation. I know the notation a little, but faced some new "standards" in the FreeRTOS.h file, which are:

#ifndef configASSERT
    #define configASSERT( x )
    #define configASSERT_DEFINED 0
#else
    #define configASSERT_DEFINED 1
#endif

And below that,

#ifndef INCLUDE_xTaskGetSchedulerState
    #define INCLUDE_xTaskGetSchedulerState 0
#endif

#ifndef INCLUDE_xTaskGetCurrentTaskHandle
    #define INCLUDE_xTaskGetCurrentTaskHandle 0
#endif

I've seen this x - as in xTaskGetCurrentTaskHandle - everywhere. Also, v, pd and variable names like that, like in line 728 of the header in question:

#if configENABLE_BACKWARD_COMPATIBILITY == 1
    #define eTaskStateGet eTaskGetState
    #define portTickType TickType_t
    #define xTaskHandle TaskHandle_t
    #define xQueueHandle QueueHandle_t
    #define xSemaphoreHandle SemaphoreHandle_t
    #define xQueueSetHandle QueueSetHandle_t
    #define xQueueSetMemberHandle QueueSetMemberHandle_t
    #define xTimeOutType TimeOut_t
    #define xMemoryRegion MemoryRegion_t
    #define xTaskParameters TaskParameters_t
    #define xTaskStatusType TaskStatus_t
    #define xTimerHandle TimerHandle_t
    #define xCoRoutineHandle CoRoutineHandle_t
    #define pdTASK_HOOK_CODE TaskHookFunction_t
    #define portTICK_RATE_MS portTICK_PERIOD_MS

    /* Backward compatibility within the scheduler code only - these definitions
    are not really required but are included for completeness. */
    #define tmrTIMER_CALLBACK TimerCallbackFunction_t
    #define pdTASK_CODE TaskFunction_t
    #define xListItem ListItem_t
    #define xList List_t

I've searched everywhere what would those "initials" stand for, but still could not figure that out.

So, if anyone could help me to understand this, or could show me a path or something, I'd be really grateful.

回答1:

Looking at the man

Naming Conventions

The RTOS kernel and demo application source code use the following conventions:

Variables

Variables of type uint32_t are prefixed ul, where the 'u' denotes unsigned and the 'l' denotes long.

Variables of type uint16_t are prefixed us, where the 'u' denotes 'unsigned' and the 's' denotes short.

Variables of type uint8_t are prefixed uc, where the 'u' denotes 'unsigned' and the 'c' denotes char.

Variables of non stdint types are prefixed x. Examples include BaseType_t and TickType_t, which are portable layer defined typedefs for the natural or most efficient type for the architecture and the type used to hold the RTOS tick count respectively.

Unsigned variables of non stdint types have an additional prefix u. For example variables of type UBaseType_t (unsigned BaseType_t) are prefixed ux.

Variables of type size_t are also prefixed x.

Enumerated variables are prefixed e

Pointers have an additional prefixed p, for example a pointer to a uint16_t will have prefix pus.

In line with MISRA guides, unqualified standard char types are only permitted to hold ASCII characters and are prefixed c.

In line with MISRA guides, variables of type char * are only permitted to hold pointers to ASCII strings and are prefixed pc.

^{Emphasis mine}

Functions

File scope static (private) functions are prefixed with prv.

API functions are prefixed with their return type, as per the convention defined for variables, with the addition of the prefix v for void.

API function names start with the name of the file in which they are defined. For example vTaskDelete is defined in tasks.c, and has a void return type.

^{Emphasis mine}

Macros

Macros are pre-fixed with the file in which they are defined. The pre-fix is lower case. For example, configUSE_PREEMPTION is defined in FreeRTOSConfig.h.

Other than the pre-fix, macros are written in all upper case, and use an underscore to separate words.

^{Emphasis mine}

来源：https://stackoverflow.com/questions/39851321/freertos-hungarian-notation

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