c - WWindow 创建文件 读取文件 写入文件

Question

我是一名学生，因此我为没有使用正确的论坛协议(protocol)而预先道歉。我是 C 语言的新手，对于 Win32 API 也确实是新手。我的作业是编写一个小型 C 程序，仅使用 Win32 I/O 系统调用将现有文件的内容复制到新文件:CreateFile()、ReadFile()、WriteFile() 等...文件名是在命令行上指定。现在我只是尝试将基本功能落实到位，然后我将专注于错误处理。此代码编译并创建一个新文件，但数据不会复制到其中。有什么建议吗？感谢您的浏览!

#include <stdio.h>
#include <stdlib.h>
#include <windows.h>

int main(int argc, char *argv[])
{
char buff[4096];
DWORD dwBytesRead, dwBytesWritten;
DWORD dwBytesToWrite = (DWORD)strlen(buff);

//open source file and read it
HANDLE source;

// Create a handle for the source file
source=CreateFile(argv[1], GENERIC_READ, 0, NULL, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, NULL);

// Check for errors
if ( source == INVALID_HANDLE_VALUE ){
    printf("Error, source file not opened.");
    exit(EXIT_FAILURE);
}
else printf("The source file is %s\n", argv[1]);

//create a new file
HANDLE target;
target = CreateFile(argv[2], GENERIC_WRITE, 0, NULL, CREATE_ALWAYS, FILE_ATTRIBUTE_NORMAL, NULL);

if ( target == INVALID_HANDLE_VALUE ){
    printf("Error, target file not created.");
    exit(EXIT_FAILURE);
}
else printf("The source file is %s\n", argv[2]);

//copy contents
ReadFile(source, buff, 4096, &dwBytesRead, NULL);
WriteFile(target, buff, dwBytesToWrite, &dwBytesWritten, NULL);

//copy complete
CloseHandle(source);
CloseHandle(target);

return 0;

}

Answer 1

正如评论中提到的，您的代码有一些错误。尝试更像这样的东西:

#include <stdio.h>
#include <stdlib.h>
#include <windows.h>

int main(int argc, char *argv[])
{
    char buff[4096];
    DWORD dwBytesRead, dwBytesWritten;

    // Open the source file
    HANDLE source = CreateFileA(argv[1], GENERIC_READ, 0, NULL, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, NULL);

    // Check for error
    if (source == INVALID_HANDLE_VALUE) {
        printf("Source file not opened. Error %u", GetLastError());
        return EXIT_FAILURE;
    }
    printf("The source file is %s\n", argv[1]);

    // Create a new file
    HANDLE target = CreateFileA(argv[2], GENERIC_WRITE, 0, NULL, CREATE_ALWAYS, FILE_ATTRIBUTE_NORMAL, NULL);

    // Check for error
    if (target == INVALID_HANDLE_VALUE) {
        printf("Target file not created. Error %u", GetLastError());
        CloseHandle(source);
        return EXIT_FAILURE;
    }
    printf("The target file is %s\n", argv[2]);

    // Copy contents
    bool ok = true;
    do {
        // Read file, check for error
        if (!ReadFile(source, buff, sizeof(buff), &dwBytesRead, NULL)) {
            printf("Source file not read from. Error %u", GetLastError());
            ok = false;
            break;
        }

        // Check for EOF reached
        if (dwBytesRead == 0) {
            break;
        }

        // Write file, check for error
        if (!WriteFile(target, buff, dwBytesRead, &dwBytesWritten, NULL)) {
            printf("Target file not written to. Error %u", GetLastError());
            ok = false;
            break;
        }
    }
    while (true);

    // Copy complete

    CloseHandle(source);
    CloseHandle(target);

    // Check for error
    if (!ok) {
        DeleteFileA(argv[2]);
        return EXIT_FAILURE;
    }

    // all OK
    return 0;
}