01最重要的規(guī)則

編寫(xiě)代碼時(shí)最重要的一條規(guī)則是：檢查周圍的代碼并嘗試模仿它。

作為維護(hù)人員，如果收到的補(bǔ)丁明顯與周圍代碼的編碼風(fēng)格不同，這是令人沮喪的。這是不尊重人的，就像某人穿著泥濘的鞋子走進(jìn)一間一塵不染的房子。

因此，無(wú)論本文推薦的是什么，如果已經(jīng)編寫(xiě)了代碼并且您正在對(duì)其進(jìn)行修補(bǔ)，請(qǐng)保持其當(dāng)前的樣式一致，即使它不是您最喜歡的樣式。

02一般性的規(guī)則

這里列出了最明顯和最重要的一般規(guī)則。在你繼續(xù)閱讀其他章節(jié)之前，請(qǐng)仔細(xì)檢查它們。

使用C99標(biāo)準(zhǔn)

不使用制表符，而是使用空格

每個(gè)縮進(jìn)級(jí)別使用4個(gè)空格

在關(guān)鍵字和左括號(hào)之間使用一個(gè)空格

在函數(shù)名和左括號(hào)之間不要使用空格

int32_t a = sum(4, 3);              /* OK */
int32_t a = sum (4, 3);             /* Wrong */

不要在變量/函數(shù)/宏/類型中使用_或前綴。這是為C語(yǔ)言本身保留的

對(duì)于嚴(yán)格的模塊私有函數(shù)，使用prv_`name`前綴

對(duì)于包含下劃線_`char的變量/函數(shù)/宏/`類型，只能使用小寫(xiě)字母

左花括號(hào)總是與關(guān)鍵字(for,`while,do,switch,`if，…)在同一行

size_t i;
for (i = 0; i < 5; ++i) {           /* OK */
}
for (i = 0; i < 5; ++i){            /* Wrong */
}
for (i = 0; i < 5; ++i)             /* Wrong */
{
}

在比較操作符和賦值操作符之前和之后使用單個(gè)空格

int32_t a;
a = 3 + 4;              /* OK */
for (a = 0; a < 5; ++a) /* OK */
a=3+4;                  /* Wrong */
a = 3+4;                /* Wrong */
for (a=0;a<5;++a)       /* Wrong */

每個(gè)逗號(hào)后用單空格

func_name(5, 4);        /* OK */
func_name(4,3);         /* Wrong */

不要初始化靜態(tài)和全局變量為0(或NULL)，讓編譯器為您做

static int32_t a;       /* OK */
static int32_t b = 4;   /* OK */
static int32_t a = 0;   /* Wrong */


void my_func(void) {
    static int32_t* ptr;/* OK */
    static char abc = 0;/* Wrong */
}

在同一行中聲明所有相同類型的局部變量

void my_func(void) {
    char a;             /* OK */
    char b;             /* Wrong, variable with char type already exists */
    char a, b;          /* OK */
}

按順序聲明局部變量

i. 自定義結(jié)構(gòu)和枚舉 ii. 整數(shù)類型，更寬的無(wú)符號(hào)類型優(yōu)先 iii. 單/雙浮點(diǎn)

int my_func(void) {
    /* 1 */
    my_struct_t my;     /* First custom structures */
    my_struct_ptr_t* p; /* Pointers too */


    /* 2 */
    uint32_t a;
    int32_t b;
    uint16_t c;
    int16_t g;
    char h;
    /* ... */


    /* 3 */
    double d;
    float f;
}

總是在塊的開(kāi)頭聲明局部變量，在第一個(gè)可執(zhí)行語(yǔ)句之前

在for循環(huán)中聲明計(jì)數(shù)器變量

/* OK */
for (size_t i = 0; i < 10; ++i)


/* OK, if you need counter variable later */
size_t i;
for (i = 0; i < 10; ++i) {
    if (...) {
        break;
    }
}
if (i * 10) {


}


/* Wrong */
size_t i;
for (i = 0; i < 10; ++i) ...

避免在聲明中使用函數(shù)調(diào)用來(lái)賦值變量，除了單個(gè)變量

void a(void) {
    /* Avoid function calls when declaring variable */
    int32_t a, b = sum(1, 2);


    /* Use this */
    int32_t a, b;
    b = sum(1, 2);


    /* This is ok */
    uint8_t a = 3, b = 4;
}

除了char、float或double之外，始終使用stdint.h標(biāo)準(zhǔn)庫(kù)中聲明的類型。例如，8位的uint8\_t等

不要使用stdbool.h庫(kù)。分別使用1或0表示真或假

/* OK */
uint8_t status;
status = 0;


/* Wrong */
#include 
bool status = true;

永遠(yuǎn)不要與真實(shí)相比較。例如，使用if(check_func()){…}替換if (check_func() * 1)

總是將指針與空值進(jìn)行比較

void* ptr;


/* ... */


/* OK, compare against NULL */
if (ptr * NULL || ptr != NULL) {


}


/* Wrong */
if (ptr || !ptr) {


}

總是使用前增量(和遞減)，而不是后增量(和遞減)

int32_t a = 0;
...


a++;            /* Wrong */
++a;            /* OK */


for (size_t j = 0; j < 10; ++j) {}  /* OK */

總是使用size_t作為長(zhǎng)度或大小變量

總是使用size_t作為長(zhǎng)度或大小變量

如果函數(shù)不應(yīng)該修改指針?biāo)赶虻膬?nèi)存，則總是使用const作為指針

如果不應(yīng)該修改函數(shù)的形參或變量，則總是使用const

/* When d could be modified, data pointed to by d could not be modified */
void
my_func(const void* d) {


}


/* When d and data pointed to by d both could not be modified */
void
my_func(const void* const d) {


}


/* Not required, it is advised */
void
my_func(const size_t len) {


}


/* When d should not be modified inside function, only data pointed to by d could be modified */
void
my_func(void* const d) {


}

當(dāng)函數(shù)可以接受任何類型的指針時(shí)，總是使用void *，不要使用uint8_t *。函數(shù)在實(shí)現(xiàn)時(shí)必須注意正確的類型轉(zhuǎn)換

/*
 * To send data, function should not modify memory pointed to by `data` variable
 * thus `const` keyword is important
 *
 * To send generic data (or to write them to file)
 * any type may be passed for data,
 * thus use `void *`
 */
/* OK example */
void send_data(const void* data, size_t len) { /* OK */
    /* Do not cast `void *` or `const void *` */
    const uint8_t* d = data;/* Function handles proper type for internal usage */
}


void send_data(const void* data, int len) {    /* Wrong, not not use int */
}

總是使用括號(hào)和sizeof操作符

不要使用變長(zhǎng)數(shù)組。使用動(dòng)態(tài)內(nèi)存分配代替標(biāo)準(zhǔn)C`malloc和自由函數(shù)，或者如果庫(kù)/項(xiàng)目提供了自定義內(nèi)存分配，使用它的實(shí)現(xiàn)看看LwMEM`，一個(gè)自定義內(nèi)存管理庫(kù)。

/* OK */
#include 
void
my_func(size_t size) {
    int32_t* arr;
    arr = malloc(sizeof(*arr) * n); /* OK, Allocate memory */
    arr = malloc(sizeof *arr * n);  /* Wrong, brackets for sizeof operator are missing */
    if (arr * NULL) {
        /* FAIL, no memory */
    }


    free(arr);  /* Free memory after usage */
}


/* Wrong */
void
my_func(size_t size) {
    int32_t arr[size];  /* Wrong, do not use VLA */
}

總是將variable與0進(jìn)行比較，除非它被視為布爾類型

永遠(yuǎn)不要將布爾處理的變量與0或1進(jìn)行比較。用NOT(!)代替

size_t length = 5;  /* Counter variable */
uint8_t is_ok = 0;  /* Boolean-treated variable */
if (length)         /* Wrong, length is not treated as boolean */
if (length > 0)     /* OK, length is treated as counter variable containing multi values, not only 0 or 1 */
if (length * 0)    /* OK, length is treated as counter variable containing multi values, not only 0 or 1 */


if (is_ok)          /* OK, variable is treated as boolean */
if (!is_ok)         /* OK, -||- */
if (is_ok * 1)     /* Wrong, never compare boolean variable against 1! */
if (is_ok * 0)     /* Wrong, use ! for negative check */

對(duì)于注釋，總是使用/*`comment */`，即使是單行注釋

在頭文件中總是包含帶有extern關(guān)鍵字的c++檢查

每個(gè)函數(shù)都必須包含doxygen-enabled注釋，即使函數(shù)是靜態(tài)的

使用英文名稱/文本的函數(shù)，變量，注釋

變量使用小寫(xiě)字母

如果變量包含多個(gè)名稱，請(qǐng)使用下劃線。force_redraw。不要使用forceRedraw

對(duì)于C標(biāo)準(zhǔn)庫(kù)的包含文件，請(qǐng)始終使用<和>。例如，#`include < stdlib.h`?>

對(duì)于自定義庫(kù)，請(qǐng)始終使用""。例如，#`include“my_library.h`”

當(dāng)轉(zhuǎn)換為指針類型時(shí)，總是將星號(hào)與類型對(duì)齊，例如。uint8_t* t = (uint8_t*)var_width_diff_type

始終尊重項(xiàng)目或庫(kù)中已經(jīng)使用的代碼風(fēng)格

03注釋相關(guān)的規(guī)則

不允許以//開(kāi)頭的注釋?？偸鞘褂芒?comment */，即使是單行注釋

對(duì)于多行注釋，每行使用空格+星號(hào)

/*
 * This is multi-line comments,
 * written in 2 lines (ok)
 */


/**
 * Wrong, use double-asterisk only for doxygen documentation
 */


/*
* Single line comment without space before asterisk (wrong)
*/


/*
 * Single line comment in multi-line configuration (wrong)
 */


/* Single line comment (ok) */

注釋時(shí)使用12個(gè)縮進(jìn)(12 * 4個(gè)空格)偏移量。如果語(yǔ)句大于12個(gè)縮進(jìn)，將注釋4-空格對(duì)齊(下面的例子)到下一個(gè)可用縮進(jìn)

void my_func(void) {
    char a, b;


    a = call_func_returning_char_a(a);          /* This is comment with 12*4 spaces indent from beginning of line */
    b = call_func_returning_char_a_but_func_name_is_very_long(a);   /* This is comment, aligned to 4-spaces indent */
}

04函數(shù)定義的規(guī)則

每個(gè)可以從模塊外部訪問(wèn)的函數(shù)都必須包含函數(shù)原型(或聲明)

函數(shù)名必須小寫(xiě)，可以用下劃線\_分隔。（這個(gè)原則好像因人而異）

/* OK */
void my_func(void);
void myfunc(void);


/* Wrong */
void MYFunc(void);
void myFunc();

當(dāng)函數(shù)返回指針時(shí)，將星號(hào)對(duì)齊到返回類型

/* OK */
const char* my_func(void);
my_struct_t* my_func(int32_t a, int32_t b);


/* Wrong */
const char *my_func(void);
my_struct_t * my_func(void);

對(duì)齊所有的功能原型(使用相同/相似的功能)以提高可讀性

/* OK, function names aligned */
void        set(int32_t a);
my_type_t   get(void);
my_ptr_t*   get_ptr(void);


/* Wrong */
void set(int32_t a);
const char * get(void);

函數(shù)實(shí)現(xiàn)必須在單獨(dú)的行中包含返回類型和可選的其他關(guān)鍵字

/* OK */
int32_t
foo(void) {
    return 0;
}


/* OK */
static const char*
get_string(void) {
    return "Hello world!
";
}


/* Wrong */
int32_t foo(void) {
    return 0;
}

05變量相關(guān)的規(guī)則

使變量名全部小寫(xiě)，下劃線\_字符可選

/* OK */
int32_t a;
int32_t my_var;
int32_t myvar;


/* Wrong */
int32_t A;
int32_t myVar;
int32_t MYVar;

按類型將局部變量分組在一起

void foo(void) {
    int32_t a, b;   /* OK */
    char a;
    char b;         /* Wrong, char type already exists */
}

不要在第一個(gè)可執(zhí)行語(yǔ)句之后聲明變量

void foo(void) {
    int32_t a;
    a = bar();
    int32_t b;      /* Wrong, there is already executable statement */
}

你可以在下一個(gè)縮進(jìn)級(jí)別中聲明新的變量

int32_t a, b;
a = foo();
if (a) {
    int32_t c, d;   /* OK, c and d are in if-statement scope */
    c = foo();
    int32_t e;      /* Wrong, there was already executable statement inside block */
}

用星號(hào)聲明指針變量與類型對(duì)齊

/* OK */
char* a;


/* Wrong */
char *a;
char * a;

當(dāng)聲明多個(gè)指針變量時(shí)，可以使用星號(hào)對(duì)變量名進(jìn)行聲明

/* OK */
char *p, *n;

06結(jié)構(gòu)、枚舉類型定義

結(jié)構(gòu)名或枚舉名必須小寫(xiě)，單詞之間有下劃線_字符

結(jié)構(gòu)或枚舉可以包含typedef關(guān)鍵字

所有結(jié)構(gòu)成員都必須小寫(xiě)

所有枚舉成員必須是大寫(xiě)的

結(jié)構(gòu)/枚舉必須遵循doxygen文檔語(yǔ)法

在聲明結(jié)構(gòu)體時(shí)，它可以使用以下三種不同的選項(xiàng)之一:

1. 當(dāng)結(jié)構(gòu)體僅用名稱聲明時(shí)，它的名稱后不能包含_t后綴。

struct struct_name {
    char* a;
    char b;
};

2. 當(dāng)只使用typedef聲明結(jié)構(gòu)時(shí)，它的名稱后面必須包含_t后綴。

typedef struct {
    char* a;
    char b;
} struct_name_t;

3. 當(dāng)結(jié)構(gòu)用name和typedef聲明時(shí)，它不能包含t作為基本名稱，它必須在它的名稱后面包含t后綴作為typedef部分。

typedef struct struct_name {
    char* a;
    char b;
    char c;
} struct_name_t;

錯(cuò)誤聲明的例子及其建議的糾正：

/* a and b must be separated to 2 lines */
/* Name of structure with typedef must include _t suffix */
typedef struct {
    int32_t a, b;
} a;


/* Corrected version */
typedef struct {
    int32_t a;
    int32_t b;
} a_t;


/* Wrong name, it must not include _t suffix */
struct name_t {
    int32_t a;
    int32_t b;
};


/* Wrong parameters, must be all uppercase */
typedef enum {
    MY_ENUM_TESTA,
    my_enum_testb,
} my_enum_t;

在聲明時(shí)初始化結(jié)構(gòu)時(shí)，使用C99初始化風(fēng)格

/* OK */
a_t a = {
    .a = 4,
    .b = 5,
};


/* Wrong */
a_t a = {1, 2};

當(dāng)為函數(shù)句柄引入new`typedef時(shí)，使用_fn`后綴

/* Function accepts 2 parameters and returns uint8_t */
/* Name of typedef has `_fn` suffix */
typedef uint8_t (*my_func_typedef_fn)(uint8_t p1, const char* p2);

07復(fù)合語(yǔ)句規(guī)則

每個(gè)復(fù)合語(yǔ)句必須包括左花括號(hào)和右花括號(hào)，即使它只包含1個(gè)嵌套語(yǔ)句

每個(gè)復(fù)合語(yǔ)句必須包含單個(gè)縮進(jìn);嵌套語(yǔ)句時(shí)，每個(gè)嵌套包含1個(gè)縮進(jìn)大小

/* OK */
if (c) {
    do_a();
} else {
    do_b();
}


/* Wrong */
if (c)
    do_a();
else
    do_b();


/* Wrong */
if (c) do_a();
else do_b();

在if或if-else-if語(yǔ)句的情況下，else必須與第一條語(yǔ)句的右括號(hào)在同一行

/* OK */
if (a) {


} else if (b) {


} else {


}


/* Wrong */
if (a) {


}
else {


}


/* Wrong */
if (a) {


}
else
{


}

在do-while語(yǔ)句的情況下，while部分必須與do部分的右括號(hào)在同一行

/* OK */
do {
    int32_t a;
    a = do_a();
    do_b(a);
} while (check());


/* Wrong */
do
{
/* ... */
} while (check());


/* Wrong */
do {
/* ... */
}
while (check());

每一個(gè)開(kāi)括號(hào)都需要縮進(jìn)

if (a) {
    do_a();
} else {
    do_b();
    if (c) {
        do_c();
    }
}

不要做沒(méi)有花括號(hào)的復(fù)合語(yǔ)句，即使是單個(gè)語(yǔ)句。下面的例子展示了一些不好的做法

if (a) do_b();
else do_c();


if (a) do_a(); else do_b();

空while循環(huán)、do-while循環(huán)或for循環(huán)必須包含花括號(hào)

/* OK */
while (is_register_bit_set()) {}


/* Wrong */
while (is_register_bit_set());
while (is_register_bit_set()) { }
while (is_register_bit_set()) {
}

如果while(或for、do-while等)為空(嵌入式編程中也可能是這種情況)，請(qǐng)使用空的單行括號(hào)

/* Wait for bit to be set in embedded hardware unit
uint32_t* addr = HW_PERIPH_REGISTER_ADDR;


/* Wait bit 13 to be ready */
while (*addr & (1 << 13)) {}        /* OK, empty loop contains no spaces inside curly brackets */
while (*addr & (1 << 13)) { }       /* Wrong */
while (*addr & (1 << 13)) {         /* Wrong */


}
while (*addr & (1 << 13));          /* Wrong, curly brackets are missing. Can lead to compiler warnings or unintentional bugs */

盡量避免在循環(huán)塊內(nèi)遞增變量，參見(jiàn)示例

/* Not recommended */
int32_t a = 0;
while (a < 10) {
    .
    ..
    ...
    ++a;
}


/* Better */
for (size_t a = 0; a < 10; ++a) {


}


/* Better, if inc may not happen in every cycle */
for (size_t a = 0; a < 10; ) {
    if (...) {
        ++a;
    }
}

08分支語(yǔ)句規(guī)則

為每個(gè)case語(yǔ)句添加單個(gè)縮進(jìn)

使用額外的單縮進(jìn)break語(yǔ)句在每個(gè)case或default

/* OK, every case has single indent */
/* OK, every break has additional indent */
switch (check()) {
    case 0:
        do_a();
        break;
    case 1:
        do_b();
        break;
    default:
        break;
}


/* Wrong, case indent missing */
switch (check()) {
case 0:
    do_a();
    break;
case 1:
    do_b();
    break;
default:
    break;
}


/* Wrong */
switch (check()) {
    case 0:
        do_a();
    break;      /* Wrong, break must have indent as it is under case */
    case 1:
    do_b();     /* Wrong, indent under case is missing */
    break;
    default:
        break;
}

總是包含default語(yǔ)句

/* OK */
switch (var) {
    case 0:
        do_job();
        break;
    default: break;
}


/* Wrong, default is missing */
switch (var) {
    case 0:
        do_job();
        break;
}

如果需要局部變量，則使用花括號(hào)并在里面放入break語(yǔ)句。將左花括號(hào)放在case語(yǔ)句的同一行

switch (a) {
    /* OK */
    case 0: {
        int32_t a, b;
        char c;
        a = 5;
        /* ... */
        break;
    }


    /* Wrong */
    case 1:
    {
        int32_t a;
        break;
    }


    /* Wrong, break shall be inside */
    case 2: {
        int32_t a;
    }
    break;
}

09宏和預(yù)處理指令

總是使用宏而不是文字常量，特別是對(duì)于數(shù)字

所有的宏必須是全大寫(xiě)的，并帶有下劃線\_字符(可選)，除非它們被明確標(biāo)記為function，將來(lái)可能會(huì)被常規(guī)函數(shù)語(yǔ)法替換

/* OK */
#define MY_MACRO(x)         ((x) * (x))


/* Wrong */
#define square(x)           ((x) * (x))
總是用圓括號(hào)保護(hù)輸入?yún)?shù)
/* OK */
#define MIN(x, y)           ((x) < (y) ? (x) : (y))


/* Wrong */
#define MIN(x, y)           x < y ? x : y

總是用括號(hào)保護(hù)最終的宏計(jì)算

/* Wrong */
#define MIN(x, y)           (x) < (y) ? (x) : (y)
#define SUM(x, y)           (x) + (y)


/* Imagine result of this equation using wrong SUM implementation */
int32_t x = 5 * SUM(3, 4);  /* Expected result is 5 * 7 = 35 */
int32_t x = 5 * (3) + (4);  /* It is evaluated to this, final result = 19 which is not what we expect */


/* Correct implementation */
#define MIN(x, y)           ((x) < (y) ? (x) : (y))
#define SUM(x, y)           ((x) + (y))

當(dāng)宏使用多個(gè)語(yǔ)句時(shí)，使用do-while(0)語(yǔ)句保護(hù)它

typedef struct {
    int32_t px, py;
} point_t;
point_t p;                  /* Define new point */


/* Wrong implementation */


/* Define macro to set point */
#define SET_POINT(p, x, y)  (p)->px = (x); (p)->py = (y)    /* 2 statements. Last one should not implement semicolon */


SET_POINT(&p, 3, 4);        /* Set point to position 3, 4. This evaluates to... */
(&p)->px = (3); (&p)->py = (4); /* ... to this. In this example this is not a problem. */


/* Consider this ugly code, however it is valid by C standard (not recommended) */
if (a)                      /* If a is true */
    if (b)                  /* If b is true */
        SET_POINT(&p, 3, 4);/* Set point to x = 3, y = 4 */
    else
        SET_POINT(&p, 5, 6);/* Set point to x = 5, y = 6 */


/* Evaluates to code below. Do you see the problem? */
if (a)
    if (b)
        (&p)->px = (3); (&p)->py = (4);
    else
        (&p)->px = (5); (&p)->py = (6);


/* Or if we rewrite it a little */
if (a)
    if (b)
        (&p)->px = (3);
        (&p)->py = (4);
    else
        (&p)->px = (5);
        (&p)->py = (6);


/*
 * Ask yourself a question: To which `if` statement `else` keyword belongs?
 *
 * Based on first part of code, answer is straight-forward. To inner `if` statement when we check `b` condition
 * Actual answer: Compilation error as `else` belongs nowhere
 */


/* Better and correct implementation of macro */
#define SET_POINT(p, x, y)  do { (p)->px = (x); (p)->py = (y); } while (0)    /* 2 statements. No semicolon after while loop */
/* Or even better */
#define SET_POINT(p, x, y)  do {       /* Backslash indicates statement continues in new line */
    (p)->px = (x);                  
    (p)->py = (y);                  
} while (0)                             /* 2 statements. No semicolon after while loop */


/* Now original code evaluates to */
if (a)
    if (b)
        do { (&p)->px = (3); (&p)->py = (4); } while (0);
    else
        do { (&p)->px = (5); (&p)->py = (6); } while (0);


/* Every part of `if` or `else` contains only `1` inner statement (do-while), hence this is valid evaluation */


/* To make code perfect, use brackets for every if-ifelse-else statements */
if (a) {                    /* If a is true */
    if (b) {                /* If b is true */
        SET_POINT(&p, 3, 4);/* Set point to x = 3, y = 4 */
    } else {
        SET_POINT(&p, 5, 6);/* Set point to x = 5, y = 6 */
    }
}

不縮進(jìn)子語(yǔ)句內(nèi)#if語(yǔ)句

/* OK */
#if defined(XYZ)
#if defined(ABC)
/* do when ABC defined */
#endif /* defined(ABC) */
#else /* defined(XYZ) */
/* Do when XYZ not defined */
#endif /* !defined(XYZ) */


/* Wrong */
#if defined(XYZ)
    #if defined(ABC)
        /* do when ABC defined */
    #endif /* defined(ABC) */
#else /* defined(XYZ) */
    /* Do when XYZ not defined */
#endif /* !defined(XYZ) */
文檔

文檔化的代碼允許doxygen解析和通用的html/pdf/latex輸出，因此正確地執(zhí)行是非常重要的。

對(duì)變量、函數(shù)和結(jié)構(gòu)/枚舉使用doxygen支持的文檔樣式

經(jīng)常使用作為doxygen，不要使用@

始終使用5x4空格(5個(gè)制表符)作為文本行開(kāi)始的偏移量

/**
 * rief           Holds pointer to first entry in linked list
 *                  Beginning of this text is 5 tabs (20 spaces) from beginning of line
 */
static
type_t* list;

每個(gè)結(jié)構(gòu)/枚舉成員都必須包含文檔

注釋的開(kāi)頭使用12x4空格偏移量

/** * rief           This is point struct * 
ote            This structure is used to calculate all point *                      related stuff */typedef struct {    int32_t x;                                  /*!< Point X coordinate */    int32_t y;                                  /*!< Point Y coordinate */    int32_t size;                               /*!< Point size.                                                    Since comment is very big,                                                    you may go to next line */} point_t;/** * rief           Point color enumeration */typedef enum {    COLOR_RED,                                  /*!< Red color. This comment has 12x4                                                    spaces offset from beginning of line */    COLOR_GREEN,                                /*!< Green color */    COLOR_BLUE,                                 /*!< Blue color */} point_color_t;

函數(shù)的文檔必須在函數(shù)實(shí)現(xiàn)中編寫(xiě)(通常是源文件)

函數(shù)必須包括簡(jiǎn)要和所有參數(shù)文檔

如果每個(gè)參數(shù)分別為in或out輸入和輸出，則必須注意

如果函數(shù)返回某個(gè)值，則必須包含返回形參。這不適用于void函數(shù)

函數(shù)可以包含其他doxygen關(guān)鍵字，如note或warning

在參數(shù)名和描述之間使用冒號(hào):

/**
 * rief           Sum `2` numbers
 * param[in]       a: First number
 * param[in]       b: Second number
 * 
eturn          Sum of input values
 */
int32_t
sum(int32_t a, int32_t b) {
    return a + b;
}


/**
 * rief           Sum `2` numbers and write it to pointer
 * 
ote            This function does not return value, it stores it to pointer instead
 * param[in]       a: First number
 * param[in]       b: Second number
 * param[out]      result: Output variable used to save result
 */
void
void_sum(int32_t a, int32_t b, int32_t* result) {
    *result = a + b;
}

如果函數(shù)返回枚舉的成員，則使用ref關(guān)鍵字指定哪個(gè)成員

/**
 * rief           My enumeration
 */
typedef enum {
    MY_ERR,                                     /*!< Error value */
    MY_OK                                       /*!< OK value */
} my_enum_t;


/**
 * rief           Check some value
 * 
eturn          
ef MY_OK on success, member of 
ef my_enum_t otherwise
 */
my_enum_t
check_value(void) {
    return MY_OK;
}

對(duì)常量或數(shù)字使用符號(hào)(' NULL ' => NULL)

/**
 * rief           Get data from input array
 * param[in]       in: Input data
 * 
eturn          Pointer to output data on success, `NULL` otherwise
 */
const void *
get_data(const void* in) {
    return in;
}

宏的文檔必須包括hideinitializer doxygen命令

/**
 * rief           Get minimal value between `x` and `y`
 * param[in]       x: First value
 * param[in]       y: Second value
 * return          Minimal value between `x` and `y`
 * hideinitializer
 */
#define MIN(x, y)       ((x) < (y) ? (x) : (y))

10頭/源文件

在文件末尾留下一個(gè)空行

每個(gè)文件都必須包括文件的doxygen注釋和后跟空行的簡(jiǎn)要描述(使用doxygen時(shí))

/**
 * file            template.h
 * rief           Template include file
 */
                    /* Here is empty line */

每個(gè)文件(頭文件或源文件)必須包含許可證(開(kāi)始注釋包括單個(gè)星號(hào)，因?yàn)閐oxygen必須忽略這個(gè))

使用與項(xiàng)目/庫(kù)已經(jīng)使用的相同的許可證

/**
 * file            template.h
 * rief           Template include file
 */


/*
 * Copyright (c) year FirstName LASTNAME
 *
 * Permission is hereby granted, free of charge, to any person
 * obtaining a copy of this software and associated documentation
 * files (the "Software"), to deal in the Software without restriction,
 * including without limitation the rights to use, copy, modify, merge,
 * publish, distribute, sublicense, and/or sell copies of the Software,
 * and to permit persons to whom the Software is furnished to do so,
 * subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be
 * included in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
 * OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE
 * AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
 * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
 * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
 * OTHER DEALINGS IN THE SOFTWARE.
 *
 * This file is part of library_name.
 *
 * Author:          FirstName LASTNAME 
 */

頭文件必須包含保護(hù)符#ifndef

頭文件必須包含c++檢查

在c++檢查之外包含外部頭文件

首先用STL`C`文件包含外部頭文件，然后是應(yīng)用程序自定義文件

頭文件必須包含其他所有頭文件，以便正確編譯，但不能包含更多頭文件(如果需要，.c應(yīng)該包含其余的頭文件)

頭文件必須只公開(kāi)模塊公共變量/類型/函數(shù)

在頭文件中使用extern作為全局模塊變量，稍后在源文件中定義它們

/* file.h ... */
#ifndef ...


extern int32_t my_variable; /* This is global variable declaration in header */


#endif


/* file.c ... */
int32_t my_variable;        /* Actually defined in source */

不要把.c文件包含在另一個(gè).c文件中

.c文件應(yīng)該首先包含相應(yīng)的.h文件，然后是其他文件，除非另有明確的必要

在頭文件中不包含模塊私有聲明

頭文件示例(示例中沒(méi)有l(wèi)icense)

/* License comes here */
#ifndef TEMPLATE_HDR_H
#define TEMPLATE_HDR_H


/* Include headers */


#ifdef __cplusplus
extern "C" {
#endif /* __cplusplus */


/* File content here */


#ifdef __cplusplus
}
#endif /* __cplusplus */


#endif /* TEMPLATE_HDR_H */

審核編輯：劉清