通过 WinInet 下载数据

Question

所以有一个代码，可以下载大小不大于 1024*100 字节的数据。代码来自https://rsdn.org/article/inet/inetapi.xml。

据我了解，InternetReadFile 在每次调用之后都应该继续读取字符数，否则它毫无意义，因为它会返回相同的数据。我红色，有一个函数，可以移动读取开始指针。我要使用它吗？

HINTERNET hInternetSession;
HINTERNET hURL;
char cBuffer[1024*100];            // I'm only going to access 1K of info.
BOOL bResult;
DWORD dwBytesRead;

// Make internet connection.
hInternetSession = InternetOpen(
    L"tes", // agent
    INTERNET_OPEN_TYPE_PRECONFIG,  // access
    NULL, NULL, 0);                // defaults

// Make connection to desired page.
hURL = InternetOpenUrl(
    hInternetSession,                       // session handle
    L"https://www.google.com.ua/images/branding/googlelogo/1x/googlelogo_color_272x92dp.png",  // URL to access
    NULL, 0, 0, 0);                         // defaults

// Read page into memory buffer.
while(bResult = InternetReadFile(
    hURL,              // handle to URL
    (LPSTR)cBuffer,    // pointer to buffer
    (DWORD)1024 * 100,       // size of buffer
    &dwBytesRead)==TRUE&&dwBytesRead>0) // pointer to var to hold return value

// Close down connections.
InternetCloseHandle(hURL);
InternetCloseHandle(hInternetSession);

DWORD dwTemp;
HANDLE hFile = CreateFile(L"googlelogo_color_272x92dp.png", GENERIC_WRITE, 0, NULL,
    CREATE_ALWAYS, FILE_ATTRIBUTE_NORMAL, NULL);
if (INVALID_HANDLE_VALUE == hFile) {
    return 0;
}
WriteFile(hFile, cBuffer, sizeof(cBuffer), &dwTemp, NULL);

问题：我无法读取超过 1024*1024 字节，程序崩溃，当创建 char[1024*1024]

Answer 1

这是一个完整的程序。感谢@RbMm

#include <windows.h>
#include <wininet.h>

#pragma comment(lib,"wininet")


int main(int argc, char* argv[])
{
HINTERNET hInternetSession;
HINTERNET hURL;
            // I'm only going to access 1K of info.
BOOL bResult;
DWORD dwBytesRead=1;

// Make internet connection.
hInternetSession = InternetOpen(
    L"tes", // agent
    INTERNET_OPEN_TYPE_PRECONFIG,  // access
    NULL, NULL, 0);                // defaults

// Make connection to desired page.
hURL = InternetOpenUrl(
    hInternetSession,                       // session handle
    L"http://wallpapers-images.ru/1920x1080/nature/wallpapers/wallpapers-nature-1.jpg",  // URL to access
    NULL, 0, 0, 0);                         // defaults

// Read page into memory buffer.

char buf[1024];

DWORD dwTemp;
HANDLE hFile = CreateFile(L"пример.jpg", GENERIC_WRITE, 0, NULL,
    CREATE_ALWAYS, FILE_ATTRIBUTE_NORMAL, NULL);

if (INVALID_HANDLE_VALUE == hFile) {
    return 0;
}

for (;dwBytesRead>0;)
{
    InternetReadFile(hURL, buf, (DWORD)sizeof(buf), &dwBytesRead);
    WriteFile(hFile, buf, dwBytesRead, &dwTemp, NULL);
}

// Close down connections.
InternetCloseHandle(hURL);
InternetCloseHandle(hInternetSession);

CloseHandle(hFile);


return 0;
}