我在开发类似于桌面加速球的软件，但是不知道要调用什么API来获取系统运行内存，求各位大神指教，拜托了。
如果有代码的话，就更好了。
我在这里先谢谢各位大神了！

Option Explicit
Private Type MEMORYSTATUS
memLength As Long
memMemoryLoad As Long
memTotalPhys As Long
memAvailPhys As Long
memTotalPageFile As Long
memAvailPageFile As Long
memTotalVirtual As Long
memAvailVirtual As Long
End Type
Private Declare Sub GlobalMemoryStatus Lib "kernel32" (lpBuffer As MEMORYSTATUS)
Function Memory(lType As Long) As Long
Const clKB As Long = 1024
Dim tMS As MEMORYSTATUS
tMS.memLength = Len(tMS)
GlobalMemoryStatus tMS
Select Case lType
Case 1
Memory = tMS.memMemoryLoad
Case 2
Memory = tMS.memTotalPhys / clKB
Case 3
Memory = tMS.memAvailPhys / clKB
Case 4
Memory = tMS.memTotalPageFile / clKB
Case 5
Memory = tMS.memAvailPageFile / clKB
Case 6
Memory = tMS.memTotalVirtual / clKB
Case 7
Memory = tMS.memAvailVirtual / clKB
Case Else
'Invalid number
Memory = -1
End Select
End Function

如果是桌面加速球这样的还需要获取每一个进程的内存占用，然后区分必须进程和次要进程，最后对次要进程进行处理。这个难度很大

那接下来我要怎么使用呢？比如加速球上有一个钟和一个标签，如何调用这些代码呢？

你说的是timer吧，钟……
昨天忘记说了，GlobalMemoryStatus适用于小内存情况，较大内存最好用GlobalMemoryStatusEx
声明

Private Type LARGE_INTEGER

 LowPart As Long

 HighPart As Long
End Type
Private Type MEMORYSTATUSEX

 dwLength As Long

 dwMemoryLoad As Long

 ullTotalPhys As LARGE_INTEGER

 ullAvailPhys As LARGE_INTEGER

 ullTotalPageFile As LARGE_INTEGER

 ullAvailPageFile As LARGE_INTEGER

 ullTotalVirtual As LARGE_INTEGER

 ullAvailVirtual As LARGE_INTEGER

 ullAvailExtendedVirtual As LARGE_INTEGER
End Type
Private Declare Function GlobalMemoryStatusEx Lib "kernel32.dll" (ByRef lpBuffer As MEMORYSTATUSEX) As Long
Private Declare Sub CopyMemory Lib "kernel32.dll" Alias "RtlMoveMemory" (Destination As Any, Source As Any, ByVal Length As Long)

在label1中显示内存信息

Private Sub DisplayMemory()
Dim MemStat As MEMORYSTATUSEX

 
Dim TotalPhys As Currency
Dim AvailPhys As Currency

 
Dim POPSize As Currency

 
Dim TotalPageFile As Currency
Dim AvailPageFile As Currency

 
Dim TotalVirtual As Currency
Dim AvailVirtual As Currency
With MemStat
MemStat.dwLength = Len(MemStat)
GlobalMemoryStatusEx MemStat
POPSize = .dwLength

 
TotalPhys = Int(LargeIntToCurrency(.ullTotalPhys) / 1024 ^ 2)
AvailPhys = Int(LargeIntToCurrency(.ullAvailPhys) / 1024 ^ 2)

 
TotalPageFile = Int(LargeIntToCurrency(.ullTotalPageFile) / 1024 ^ 2)
AvailPageFile = Int(LargeIntToCurrency(.ullAvailPageFile) / 1024 ^ 2)

 
TotalVirtual = Int(LargeIntToCurrency(.ullTotalVirtual) / 1024 ^ 2)
AvailVirtual = Int(LargeIntToCurrency(.ullAvailVirtual) / 1024 ^ 2)

 
Label1.Caption = "入栈大小:" & POPSize & " Bytes" & vbCrLf & _
"物理内存大小:" & TotalPhys & "MB" & vbCrLf & _
"已用物理内存:" & TotalPhys - AvailPhys & "MB" & vbCrLf & _
"可用物理内存:" & Int((AvailPhys / TotalPhys) * 100) & "%" & vbCrLf & _
"可用物理内存:" & AvailPhys & "MB" & vbCrLf & vbCrLf & _
"虚拟内存大小:" & TotalVirtual & "MB" & vbCrLf & _
"已用虚拟内存:" & TotalVirtual - AvailVirtual & "MB" & vbCrLf & _
"可用虚拟内存:" & Int((AvailVirtual / TotalVirtual) * 100) & "%" & vbCrLf & _
"可用虚拟内存:" & AvailVirtual & "MB" & vbCrLf & vbCrLf & _
" 总计:" & TotalPageFile & "MB" & vbCrLf & _
" 已用:" & TotalPageFile - AvailPageFile & "MB" & vbCrLf & _
" 可用:" & AvailPageFile & "MB" & vbCrLf & vbCrLf & _
"-------------------------" & vbCrLf & _
"已经使用了: " & .dwMemoryLoad & "%"
Me.Caption = "已用内存:" & .dwMemoryLoad & "%"
End With
End Sub

Private Function LargeIntToCurrency(liInput As LARGE_INTEGER) As Currency
CopyMemory LargeIntToCurrency, liInput, LenB(liInput)
LargeIntToCurrency = LargeIntToCurrency * 10000
End Function

利用Timer控件实时刷新

Private Sub Timer1_Timer()
  DisplayMemory
End Sub