标签: fwrite

有人可以检查我的代码,我不知道它有什么问题.每当我执行代码时,我都会在标题中得到错误.

<?php
$file = "newfile.txt";

$text = "This is a text line. ";

$handle = fopen($file, "w");

fwrite($handle, $text);
fclose($handle);

$handle = fopen($file, "a");

$text = "Here are more text lines to insert."
fwrite($handle, $text);
fclose($handle);

include ($file);

?>

我正在使用C的fwrite函数将3个整数的数组写入文件,但是当使用gedit(使用Unicode UTF-8)打开输出文件时,我收到以下错误:

There was a problem opening the file.  The file you opened has invalid characters.  If you continue editing this file, you could corrupt the document.

这是相关的代码段:

char* imageFile = "image.txt";
FILE* imageFilePtr = fopen(imageFile, "w");

int scores[3] = {69, 70, 71};
fwrite(scores, sizeof(int), sizeof(scores), imageFilePtr);

当我使用十六进制读取器,如"xxd"时,我在终端中得到以下内容:

0000000: 4500 0000 4600 0000 4700 0000 7031 7108  E...F...G...p1q.
0000010: 0830 7108 2987 0408 2087 0408 0460 cebf  .0q.)... ....`..
0000020: 0100 0000 0000 0000 0000 0000 0000 0000  ................

请记住,在我的环境中,sizeof(int)是4个字节.因此,我可以看到十进制中的69,70和71如何以xxd显示的十六进制中的45,46和47打印到文件中.但是,"4700 …

fwrite({0x89, 0x50, 0x4e, 0x47, 0x0d, 0x0a, 0x1a, 0x0a, 0x00, 0x00, 0x00, 0x0d, 0x49, 0x48, 0x44, 0x52, 0x00, 0x00, 0x00, 0x10, 0x00, 0x00, 0x00, 0x10, 0x08, 0x06, 0x00, 0x00, 0x00, 0x1f, 0xf3, 0xff, 0x61, 0x00, 0x00, 0x01, 0x8a, 0x49, 0x44, 0x41, 0x54, 0x38, 0x8d, 0xa5, 0x93, 0xb1, 0x72, 0xd4, 0x30, 0x10, 0x86, 0xbf, 0x95, 0xad, 0xcc, 0xc4, 0x30, 0xa4, 0xb9, 0xe6, 0x68, 0x68, 0xd3, 0x50, 0xf3, 0x42, 0xbc, 0x0e, 0xcf, 0xc3, 0x0c, 0x1d, 0x33, 0x69, 0x68, 0xa8, 0xaf, 0x09, 0xc5, 0x51, …

我试图用来fread()确定文件是否是 jpeg，我的想法是使用fread()读取文件的标题以确保它是 jpeg，然后，如果是 - 复制文件。我知道标准的 jpeg 标头是0xff 0xd8 0xff 0xe(0 to f)，所以我制作了一个程序来读取文件的前四个字节。

#include <stdio.h>
#include <stdint.h>

typedef uint8_t BYTE;

int main (int argc, char *argv[])
{
    FILE *in = fopen(argv[1], "rb");
    
    FILE *out = fopen("output.jpg", "wb");
    
    BYTE buffer [4096];
    
    while (fread(buffer, 1, sizeof(buffer), in))
    {
        if ((buffer[0] == 0xff) & (buffer[1] == 0xd8) & (buffer[2] == 0xff) & ((buffer[3] & 0xf0) == 0xe0))
        {
            fwrite(buffer, 1, sizeof(buffer), out);
        }
    }
    
    fclose(in);
    fclose(out);
}

但是，在运行程序后，当我尝试打开 …