用C实现打印所有进程

用C实现打印所有进程

// struct PROCESSENTRY32
Describes an entry from a list that enumerates the processes residing in the system address space when a snapshot was taken.

typedef struct tagPROCESSENTRY32 {
  DWORD dwSize;
  DWORD cntUsage;
  DWORD th32ProcessID;
  ULONG_PTR th32DefaultHeapID;
  DWORD th32ModuleID;
  DWORD cntThreads;
  DWORD th32ParentProcessID;
  LONG  pcPriClassBase;
  DWORD dwFlags;
  TCHAR szExeFile[MAX_PATH];
} PROCESSENTRY32;
typedef PROCESSENTRY32 *PPROCESSENTRY32;
Members
dwSize
Specifies the length, in bytes, of the structure. Before calling the Process32First function, set this member to sizeof(PROCESSENTRY32). If you do not initialize dwSize, Process32First will fail.
cntUsage
Number of references to the process. A process exists as long as its usage count is nonzero. As soon as its usage count becomes zero, a process terminates.
th32ProcessID
Identifier of the process.
th32DefaultHeapID
Identifier of the default heap for the process. The contents of this member has meaning only to the tool help functions. It is not a handle, nor is it usable by functions other than the ToolHelp functions.
th32ModuleID
Module identifier of the process. The contents of this member has meaning only to the tool help functions. It is not a handle, nor is it usable by functions other than the ToolHelp functions.
cntThreads
Number of execution threads started by the process.
th32ParentProcessID
Identifier of the process that created the process being examined.
pcPriClassBase
Base priority of any threads created by this process.
dwFlags
Reserved; do not use.
szExeFile
Path and filename of the executable file for the process.

// fucntion CreateToolhelp32Snapshot
Takes a snapshot of the processes and the heaps, modules, and threads used by the processes.

HANDLE WINAPI CreateToolhelp32Snapshot(
  DWORD dwFlags,      
  DWORD th32ProcessID 
);
Parameters
dwFlags
[in] Specifies portions of the system to include in the snapshot. This parameter can be one of the following values. Value Meaning
TH32CS_INHERIT Indicates that the snapshot handle is to be inheritable.
TH32CS_SNAPALL Equivalent to specifying TH32CS_SNAPHEAPLIST, TH32CS_SNAPMODULE, TH32CS_SNAPPROCESS, and TH32CS_SNAPTHREAD.
TH32CS_SNAPHEAPLIST Includes the heap list of the specified process in the snapshot.
TH32CS_SNAPMODULE Includes the module list of the specified process in the snapshot.
TH32CS_SNAPPROCESS Includes the process list in the snapshot.
TH32CS_SNAPTHREAD Includes the thread list in the snapshot.

th32ProcessID
[in] Specifies the process identifier. This parameter can be zero to indicate the current process. This parameter is used when the TH32CS_SNAPHEAPLIST or TH32CS_SNAPMODULE value is specified. Otherwise, it is ignored.
Return Values
Returns an open handle to the specified snapshot if successful or INVALID_HANDLE_VALUE otherwise.

Remarks
The snapshot taken by this function is examined by the other tool help functions to provide their results. Access to the snapshot is read only. The snapshot handle acts like an object handle and is subject to the same rules regarding which processes and threads it is valid in.

To retrieve an extended error status code generated by this function, use the GetLastError function.

To destroy the snapshot, use the CloseHandle function.

Example Code
For an example, see Taking a Snapshot and Viewing Processes.

Requirements
  Windows NT/2000/XP: Included in Windows 2000 and later.
  Windows 95/98/Me: Included in Windows 95 and later.
  Header: Declared in Tlhelp32.h.
  Library: Use Kernel32.lib.

Process32Next
Retrieves information about the next process recorded in a system snapshot.

BOOL WINAPI Process32Next(
  HANDLE hSnapshot,     
  LPPROCESSENTRY32 lppe 
);
Parameters
hSnapshot
[in] Handle to the snapshot returned from a previous call to the CreateToolhelp32Snapshot function.
lppe
[out] Pointer to a PROCESSENTRY32 structure.
Return Values
Returns TRUE if the next entry of the process list has been copied to the buffer or FALSE otherwise. The ERROR_NO_MORE_FILES error value is returned by the GetLastError function if no processes exist or the snapshot does not contain process information.

Remarks
To retrieve information about the first process recorded in a snapshot, use the Process32First function.

Example Code
For an example, see Taking a Snapshot and Viewing Processes.

Requirements
  Windows NT/2000/XP: Included in Windows 2000 and later.
  Windows 95/98/Me: Included in Windows 95 and later.
  Header: Declared in Tlhelp32.h.
  Library: Use Kernel32.lib.

//function CloseHandle
The CloseHandle function closes an open object handle.

BOOL CloseHandle(
  HANDLE hObject   // handle to object
);
Parameters
hObject
[in/out] Handle to an open object.
Return Values
If the function succeeds, the return value is nonzero.

If the function fails, the return value is zero. To get extended error information, call GetLastError.

Windows NT/2000/XP: Closing an invalid handle raises an exception when the application is running under a debugger. This includes closing a handle twice, and using CloseHandle on a handle returned by the FindFirstFile function.

Remarks
The CloseHandle function closes handles to the following objects:

Access token
Communications device
Console input
Console screen buffer
Event
File
File mapping
Job
Mailslot
Mutex
Named pipe
Process
Semaphore
Socket
Thread
CloseHandle invalidates the specified object handle, decrements the object's handle count, and performs object retention checks. After the last handle to an object is closed, the object is removed from the system.

Closing a thread handle does not terminate the associated thread. To remove a thread object, you must terminate the thread, then close all handles to the thread.

Use CloseHandle to close handles returned by calls to the CreateFile function. Use FindClose to close handles returned by calls to FindFirstFile.

Example Code
For an example, see Cleaning up.

Requirements
  Windows NT/2000/XP: Included in Windows NT 3.1 and later.
  Windows 95/98/Me: Included in Windows 95 and later.
  Header: Declared in Winbase.h; include Windows.h.
  Library: Use Kernel32.lib.

#include <windows.h>
#include <tlhelp32.h> //申明快照函数的头文件
#include <iostream>

using namespace std;

int main(int argc, char** argv)
{
 PROCESSENTRY32 pe;
 HANDLE  hProcess = 0;
 BOOL  bNext  = FALSE;

 //在使用这结构前，先设置其大小
 pe.dwSize = sizeof(pe);
  
  //给系统的所有进程拍一个照
 hProcess = CreateToolhelp32Snapshot(TH32CS_SNAPPROCESS, 0);
 if (hProcess == INVALID_HANDLE_VALUE)
 {
  cout << "call function failed..." << endl;

  return -1;
 }

 //遍历进程快照
 while (Process32Next(hProcess, &pe))
 {
  cout << "name: " << pe.szExeFile << "/t/t" << "id: " << pe.th32ProcessID << endl;
 }

 //删除句柄
 CloseHandle(hProcess);

 return 0;
}