> For the complete documentation index, see [llms.txt](https://docs.aic-eec.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.aic-eec.com/c-c++-for-embedded-programming/c-c++-preprocessing/pragma-directive.md).

# Pragma directive

{% hint style="info" %}

#### Pragma : เทคนิคที่ทำการเตรียมตัว Compiler ที่จะนำมาใช้งานรวมถึง option เสริมต่างๆให้กับฟังก์ชันที่กำหนด รวมถึงเลือกสถาปัตยกรรมที่จะใช้โดยจะแบ่งกรณีการใช้งานดังนี้

{% endhint %}

* ใช้ในการเลือก Compiler เช่น

```cpp
#pragma GCC
```

* ใช้ในการเพิ่ม option เสริม

```cpp
#pragma GCC push_options
```

* ใช้ในการป้องกันการใช้ฟังก์ชันบางอย่าง

```cpp
#pragma GCC poison printf
```

* ใช้ในการเลือกสถาปัตยกรรมที่ใช่ในการ Compile

```cpp
 #pragma GCC target (“arch=armv6”)
```

#### Example C++

```cpp
#include <bits/stdc++.h>
using namespace std;
	
void func1();
void func2();

#pragma startup func1
#pragma exit func2

void func1()
{
	cout << "Inside func1()\n";
}

void func2()
{
	cout << "Inside func2()\n";
}

int main()
{
	void func1();
	void func2();
	cout << "Inside main()\n";

	return 0;
}

// This code is contributed by shivanisinghss2110

```

#### Example C

```cpp
#include <stdio.h>

void func1();
void func2();

#pragma startup func1
#pragma exit func2

void func1()
{
	printf("Inside func1()\n");
}

void func2()
{
	printf("Inside func2()\n");
}

int main()
{
	void func1();
	void func2();
	printf("Inside main()\n");

	return 0;
}

```

#### Output

```cpp
Inside func1()
Inside main()
Inside func2()
```


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