已声明原型的函数的隐式声明

Question

我有这个错误代码：

helpers.c:56:13: warning: implicit declaration of function 'swap' is invalid in
C99 [-Wimplicit-function-declaration]
swap(height, width, image, i, j);
^
helpers.c:62:6: error: conflicting types for 'swap'
void swap(int height, int width, RGBTRIPLE image[height][width], int row...
^
helpers.c:56:13: note: previous implicit declaration is here
swap(height, width, image, i, j);
^
helpers.c:75:31: warning: implicit declaration of function 'value' is invalid in
C99 [-Wimplicit-function-declaration]
image_new[i][j] = value(height, width, image, i, j);
^
helpers.c:75:29: error: assigning to 'RGBTRIPLE' from incompatible type 'int'
image_new[i][j] = value(height, width, image, i, j);
^ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
helpers.c:87:11: error: conflicting types for 'value'
RGBTRIPLE value(int height, int width, RGBTRIPLE image[height][width], i...
^
helpers.c:75:31: note: previous implicit declaration is here
image_new[i][j] = value(height, width, image, i, j);
^

我知道 implicit declaration of function 与没有函数原型有关，但在我的情况下我有一个。

helpers.c

#include "helpers.h"
#include <math.h>
#include <cs50.h>

// Convert image to grayscale
void grayscale(int height, int width, RGBTRIPLE image[height][width]){
    int average = 0;
    RGBTRIPLE dot;

    for(int i = 0; i < height; i++){
        for(int j = 0; j < width; j++){
            dot = image[i][j];
            average = round((dot.rgbtRed + dot.rgbtGreen + dot.rgbtBlue) / 3.0);

            image[i][j].rgbtRed = average;
            image[i][j].rgbtGreen = average;
            image[i][j].rgbtBlue = average;
        }
    }
    return;
}

int max(int value){
    if(value > 255){
        return 255;
    }
    else{
        return value;
    }
}

// Convert image to sepia
void sepia(int height, int width, RGBTRIPLE image[height][width]){

    for(int i = 0; i < height; i++){
        for(int j = 0; j < width; j++){
            RGBTRIPLE dot = image[i][j];
            image[i][j].rgbtRed = max(round(0.393 * dot.rgbtRed + 0.769 * dot.rgbtGreen + 0.189 * dot.rgbtBlue));
            image[i][j].rgbtGreen = max(round(0.349 * dot.rgbtRed + 0.686 * dot.rgbtGreen + 0.168 * dot.rgbtBlue));
            image[i][j].rgbtBlue = max(round(0.272 * dot.rgbtRed + 0.534 * dot.rgbtGreen + 0.131 * dot.rgbtBlue));
        }
    }
    return;
}

// Reflect image horizontally
void reflect(int height, int width, RGBTRIPLE image[height][width]){
    int n;

    if(width % 2 != 0){
        n = 1;
    }

    for(int i = 0; i < height; i++){
        for(int j = 0, k = (width - n) / 2; j < k; j++){
            swap(height, width, image, i, j);
        }
    }
    return;
}

void swap(int height, int width, RGBTRIPLE image[height][width], int row, int pix){

    RGBTRIPLE temp = image[row][pix];
    image[row][pix] = image[row][width - pix];
    image[row][width - pix] = temp;
}

// Blur image
void blur(int height, int width, RGBTRIPLE image[height][width]){
    RGBTRIPLE image_new[height][width];

    for(int i = 0; i < height; i++){
        for(int j = 0; j < width; j++){
            image_new[i][j] = value(height, width, image, i, j);
        }
    }

    for(int i = 0; i < height; i++){
        for(int j = 0; j < width; j++){
            image[i][j] = image_new[i][j];
        }
    }
    return;
}

RGBTRIPLE value(int height, int width, RGBTRIPLE image[height][width], int x, int y){
    int count = 0;
    int red = 0;
    int blue = 0;
    int green = 0;
    RGBTRIPLE dot;

    for(int i = -1; i <= 1; i++){
        for(int j = -1; j <= 1; j++){
            int length = i + x;
            int spread = j + y;

            if((length >= 0) && (length < height) && (spread >= 0) && (spread < width)){
                red += image[length][spread].rgbtRed;
                blue += image[length][spread].rgbtBlue;
                green += image[length][spread].rgbtGreen;
                count++;
            }
        }
    }

    dot.rgbtRed = round((float)red / count);
    dot.rgbtBlue = round((float)blue / count);
    dot.rgbtGreen = round((float)green / count);

    return dot;
}

helpers.h

#include "bmp.h"

// Convert image to grayscale
void grayscale(int height, int width, RGBTRIPLE image[height][width]);

// Check if color value is within limit
int max(int value);

// Convert image to sepia
void sepia(int height, int width, RGBTRIPLE image[height][width]);

// Reflect image horizontally
void reflect(int height, int width, RGBTRIPLE image[height][width]);

// Swapping pixel
void swap(int height, int width, RGBTRIPLE image[height][width], int row, int pix);

// Blur image
void blur(int height, int width, RGBTRIPLE image[height][width]);

RGBTRIPLE value(int height, int width, RGBTRIPLE image[height][width], int x, int y);

bmp.h

    // BMP-related data types based on Microsoft's own

#include <stdint.h>

/**
 * Common Data Types
 *
 * The data types in this section are essentially aliases for C/C++
 * primitive data types.
 *
 * Adapted from http://msdn.microsoft.com/en-us/library/cc230309.aspx.
 * See http://en.wikipedia.org/wiki/Stdint.h for more on stdint.h.
 */
typedef uint8_t  BYTE;
typedef uint32_t DWORD;
typedef int32_t  LONG;
typedef uint16_t WORD;

/**
 * BITMAPFILEHEADER
 *
 * The BITMAPFILEHEADER structure contains information about the type, size,
 * and layout of a file that contains a DIB [device-independent bitmap].
 *
 * Adapted from http://msdn.microsoft.com/en-us/library/dd183374(VS.85).aspx.
 */
typedef struct
{
    WORD   bfType;
    DWORD  bfSize;
    WORD   bfReserved1;
    WORD   bfReserved2;
    DWORD  bfOffBits;
} __attribute__((__packed__))
BITMAPFILEHEADER;

/**
 * BITMAPINFOHEADER
 *
 * The BITMAPINFOHEADER structure contains information about the
 * dimensions and color format of a DIB [device-independent bitmap].
 *
 * Adapted from http://msdn.microsoft.com/en-us/library/dd183376(VS.85).aspx.
 */
typedef struct
{
    DWORD  biSize;
    LONG   biWidth;
    LONG   biHeight;
    WORD   biPlanes;
    WORD   biBitCount;
    DWORD  biCompression;
    DWORD  biSizeImage;
    LONG   biXPelsPerMeter;
    LONG   biYPelsPerMeter;
    DWORD  biClrUsed;
    DWORD  biClrImportant;
} __attribute__((__packed__))
BITMAPINFOHEADER;

/**
 * RGBTRIPLE
 *
 * This structure describes a color consisting of relative intensities of
 * red, green, and blue.
 *
 * Adapted from http://msdn.microsoft.com/en-us/library/aa922590.aspx.
 */
typedef struct
{
    BYTE  rgbtBlue;
    BYTE  rgbtGreen;
    BYTE  rgbtRed;
} __attribute__((__packed__))
RGBTRIPLE;

我想不出为什么这是错误的。

当我这样做时，代码编译得很好，但在 CS50 编译器上，我得到了那些错误代码。我尝试使用我的代码，发现图像结果是正确的。所以我很困惑为什么我会收到这些错误。

编辑 1： 删除 void 类型函数中的 return 语句仍然没有消除错误。

编辑 2： Link to entire code on a online ide

编辑 4：clang -fsanitize=signed-integer-overflow -fsanitize=undefined -ggdb3 -O0 -Qunused-arguments -std=c11 -Wall -Werror -Wextra -Wno-sign-compare -Wno-unused-参数 -Wno-unused-variable -Wshadow -o filter filter.c helpers.c

我正在编译我唯一可以编译的两个文件，即 filter.c 和 helpers.c

Answer 1

当我查看代码时，我注意到在 void reflected() 和 void blur() 中，我在其中有两个自定义函数，它们是在它之后声明的，导致编译器假定自定义函数'不存在'。

要解决此问题，请将自定义函数移到调用它的函数之前以避免错误。在这种情况下，swap() 应该声明或放在 void reflected() 之前，与 RGBTRIPLE value() 和 `void blur()

的情况相同

已声明原型的函数的隐式声明

Implicit declaration of function of a declared prototype

c

c99

cs50