????#line???
????????#line???_LINE_??_FILE_????????????????????????????????????
???????????#line number [ filename ]??????????????????к?????????
#include<iostream>
using namespace std;
#line 100 "a.cpp"
int main()
{
cout<<__LINE__<<' '<<__FILE__<<endl;
system("pause");
return 0;
}
???????н????

??????????????
?????????е??????????У?#Pragma ??????????????????????????趨????????????????????????????Щ??????????#pragma???????????????????????????????????C??C++????????????????￡??????????????????е?????????????壬????????????????????е?????????????????????????
????????????: #pragma Para??????Para ???????
????message ??????????????????????????????????
????#pragma message("??????")
????code_seg?????????ó????к?????????????Σ?????????????????????????????
????#pragma code_seg(["section-name"[??"section-class"]])
????#pragma once??
?????????????????????????????????????????????Σ???????????д?????????????????C++?е???塣
????#pragma hdrstop??????????????????????????????????????????
????#pragma resource??
????#pragma resource "winform.dfm"
?????????winform.dfm????е???????????winform.dfm?а?????????????塣
????#pragma warning??????????????
??????????????3???
int main()
{
float f=3.6;
int i=f;
cout<<i<<endl;
system("pause");
return 0;
}
?????????????????????
????1>ClCompile:
????1>f.cpp
????1>c:usersgaohongchendesktop4555f.cpp(12): warning C4305: “?????”: ??“double”??“float”???
????1>c:usersgaohongchendesktop4555f.cpp(13): warning C4244: “?????”: ??“float”?????“int”????????????
??????????????????????
????#pragma warning(disable:4305)
???????????????????????
????1>ClCompile:
????1>f.cpp
????1>c:usersgaohongchendesktop4555f.cpp(13): warning C4244: “?????”: ??“float”?????“int”????????????
??????????????????????
????#pragma warning(error:4244)
????????????????????????
????1>ClCompile:
????1>f.cpp
????1>c:usersgaohongchendesktop4555f.cpp(12): warning C4305: “?????”: ??“double”??“float”???
????1>c:usersgaohongchendesktop4555f.cpp(13): error C4244: “?????”: ??“float”?????“int”????????????
????#pragma comment???????????????????????????????????????С?
?????????lib????????????????????????????????磺
????#pragma comment(lib??"wsock32.lib")
????#pragma disable??????????????????????????Ч???ú??????ù????н???????ж???????C51????y??