编码标准、测试和样式指南

/* Library includes come first... */

#include <stdlib.h>

/* ...followed by FreeRTOS includes... */

#include "FreeRTOS.h"

/* ...followed by other includes. */

#include "HardwareSpecifics.h"

/* #defines come next, bracketed where possible. */

#define A_DEFINITION	( 1 )



/*

 * Static (file private) function prototypes appear next, with comments

 * in this style - each line starting with a '*'.

 */

static void prvAFunction( uint32_t ulParameter );



/* File scope variables are the last thing before the function definitions.

Comments for variables are in this style (without each line starting with

a '*'). */

static BaseType_t xMyVariable;



/* The following separator is used after the closing bracket of each function,

with a blank line following it before the start of the next function definition. */



/*-----------------------------------------------------------*/



void vAFunction( void )

{

    /* Function definition goes here - note the separator after the closing

    curly bracket. */

}

/*-----------------------------------------------------------*/



static UBaseType_t prvNextFunction( void )

{

    /* Function definition goes here. */

}

/*-----------------------------------------------------------*/



File Layout

/* Variables are given verbose, unabbreviated, descriptive names. */

UBaseType_t uxCurrentNumberOfTasks = 0U;

TickType_t xTickCount = 0U;

uint32_t ulTopReadyPriority = 0UL;



/* Booleans use the microcontroller architecture's most efficient type, which

is defined in the kernel's portable layer as BaseType_t. */

BaseType_t xSchedulerRunning = pdFALSE;



/* Function names are always written on a single line, including the return

type.  As always, there is no space before the opening parenthesis.  There

is a space after an opening parenthesis.  There is a space before a closing

parenthesis.  There is a space after each comma.  Parameters are given

verbose, descriptive names (unlike this example!).  The opening and closing

curly brackets appear on their own lines, lined up underneath each other. */

void vAnExampleFunction( uint32_t ulParameter1, uint16_t usParameter2 )

{

/* Variable declarations are not indented, and use stdint.h defined types. */

uint8_t ucByte;



    /* Code is indented.  Curly brackets are always on their own lines

    and lined up underneath each other. */

    for( ucByte = 0U; ucByte < fileBUFFER_LENGTH; ucByte++ )

    {

        /* Indent again. */

    }

}



/* For, while, do and if constructs follow a similar pattern.  There is no

space before the opening parenthesis.  There is a space after an opening

parenthesis.  There is a space before a closing parenthesis.  There is a

space after each semicolon (if there are any).  There are spaces before and

after each operator.  No reliance is placed on operator precedence -

parenthesis are always used to make precedence explicit.  Magic numbers,

other than zero, are always replaced with a constant or #defined constant.

The opening and closing curly brackets appear on their own lines. */

for( ucByte = 0U; ucByte < fileBUFFER_LENGTH; ucByte++ )

{

}



while( ucByte < fileBUFFER_LENGTH )

{

}



/* There must be no reliance on operator precedence - every condition in a

multi-condition decision must uniquely be bracketed, as must all

sub-expressions.  Ternary and comma operators are not allowed (except for

variable declarations). See the following comment block for a preferred layout

of the following code. */

if( ( ucByte < fileBUFFER_LENGTH ) && ( ucByte != 0U ) )

{

    /* Example of no reliance on operator precedence! */

    ulResult = ( ( ulValue1 + ulValue2 ) - ulValue3 ) * ulValue4;

}



/* To improve code coverage metrics, each condition in a decision should be

tested individually.  For example, the if() statement in the code snipped

immediately above is better written as the code snippet immediately below. */

if( ucByte < fileBUFFER_LENGTH )

{

    if( ucByte != 0U )

    {

        /* Example of no reliance on operator precedence! */

        ulResult = ( ( ulValue1 + ulValue2 ) - ulValue3 ) * ulValue4;

    }

}



/* Conditional compilations are laid out and indented as per any

other code. */

#if( configUSE_TRACE_FACILITY == 1 )

{

    /* Add a counter into the TCB for tracing only. */

    pxNewTCB->uxTCBNumber = uxTaskNumber;

}

#endif



/* A space is placed after an opening square bracket, and before a closing

square bracket. */

ucBuffer[ 0 ] = 0U;

ucBuffer[ fileBUFFER_LENGTH - 1U ] = 0U;



Formatting of C Constructs