#pragma init_seg
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Syntax (See Pseudo-grammar)
#pragma init_seg({ compiler | lib | user })
Description
Use #pragma init_seg to control the order in which startup code is executed.
Code marked with #pragma init_seg(compiler) is executed before code marked with #pragma init_seg(lib), and code marked with #pragma init_seg(lib) is executed before code marked with #pragma init_seg(user).
Example
Suppose you have a project containing the following files:
| main.cpp | Unit1.cpp | Unit2.cpp |
|---|---|---|
#include <vcl.h>
#include <tchar.h>
int _tmain(int argc, _TCHAR* argv[]) {
return 0;
}
|
#include <iostream>
using namespace std;
class X {
public:
X() {
cout << "X ctor" << endl;
}
};
#pragma init_seg(lib)
static X x;
|
#include <iostream>
using namespace std;
class Y {
public:
Y() {
cout << "Y ctor" << endl;
}
};
#pragma init_seg(user)
static Y y;
|
This application displays the following (put a breakpoint on the line containing the return statement of the main function to see the console output):
X ctor Y ctor
This means that the global variable x is initialized before the global variable y. To change the initialization order, it is necessary to switch the #pragma init_seg directive options:
| main.cpp | Unit1.cpp | Unit2.cpp |
|---|---|---|
#include <vcl.h>
#include <tchar.h>
int _tmain(int argc, _TCHAR* argv[]) {
return 0;
}
|
#include <iostream>
using namespace std;
class X {
public:
X() {
cout << "X ctor" << endl;
}
};
#pragma init_seg(user)
static X x;
|
#include <iostream>
using namespace std;
class Y {
public:
Y() {
cout << "Y ctor" << endl;
}
};
#pragma init_seg(lib)
static Y y;
|
This application displays:
Y ctor X ctor