file_delete_on_close.c

Author: keineahnung2345

file_delete_on_close.c

@@ -0,0 +1,67 @@
+//#include <fileapi.h>
+//#include <WinBase.h> //FILE_FLAG_DELETE_ON_CLOSE 
+#include <windows.h> //https://stackoverflow.com/questions/4845198/fatal-error-no-target-architecture-in-visual-studio
+#include <io.h> //_open_osfhandle
+#include <fcntl.h> //_O_RDONLY,  _O_WRONLY
+#include <stdio.h>
+
+//https://stackoverflow.com/questions/12249610/c-create-file-in-memory
+//https://docs.microsoft.com/zh-tw/windows/win32/fileio/creating-and-using-a-temporary-file
+FILE* createTempFile() {
+    TCHAR szTempFileName[MAX_PATH] = { 0 };
+    TCHAR lpTempPathBuffer[MAX_PATH] = { 0 };
+
+    DWORD dwRetVal = GetTempPath(MAX_PATH,          // length of the buffer
+        lpTempPathBuffer);
+    if (dwRetVal > MAX_PATH || (dwRetVal == 0)) {
+        printf("GetTempPath failed\n");
+        return NULL;
+    }
+    //wprintf(L"temp path: %s\n", lpTempPathBuffer);
+    //temp path: C:\Users\xxx\AppData\Local\Temp\
+
+    UINT uRetVal = GetTempFileName(lpTempPathBuffer, // directory for tmp files
+        TEXT("DEMO"),     // temp file name prefix 
+        0,                // create unique name 
+        szTempFileName);  // buffer for name 
+    if (uRetVal == 0) {
+        printf("GetTempFileName failed\n");
+        return NULL;
+    }
+    //wprintf(L"temp name: %s\n", szTempFileName);
+    //temp name: C:\Users\xxx\AppData\Local\Temp\DEM6C25.tmp
+
+    HANDLE hTempFile = CreateFile((LPTSTR)szTempFileName, // file name 
+        GENERIC_READ | GENERIC_WRITE,        // open for write 
+        0,                    // do not share 
+        NULL,                 // default security 
+        CREATE_ALWAYS,        // overwrite existing
+        FILE_ATTRIBUTE_TEMPORARY | FILE_FLAG_DELETE_ON_CLOSE,// normal file 
+        NULL);                // no template 
+
+    //https://stackoverflow.com/questions/5193579/how-make-file-from-handle-in-winapi
+    int nHandle = _open_osfhandle((long)hTempFile, _O_RDONLY | _O_WRONLY);
+    if (nHandle == -1) {
+        ::CloseHandle(hTempFile);   //case 1
+        return nullptr;
+    }
+    FILE* fp = _fdopen(nHandle, "w+");
+    if (!fp) {
+        ::CloseHandle(hTempFile);  //case 2
+    }
+    return fp;
+}
+
+int main() {
+    FILE* fp = createTempFile();
+    
+    char buffer[] = { 'H','e','l', 'l','o' };
+    if (fp == NULL) {
+        printf("open failure");
+        return 1;
+    }
+    fwrite(buffer, 1, sizeof(buffer), fp);
+    fflush(fp);
+    fclose(fp);
+    return 0;
+}