#pragma Directive in C/C++

The #pragma is complier specified. for example, the code below does not work in gcc.

#pragma startup and #pragma exit:

#pragma startup func1
#pragma exit func2 

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

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

int main()
{
    printf("Inside main()\n"); 

    return ;
}  

in GCC, you can use

void __attribute__((constructor)) func1(); 

void __attribute__((destructor)) func2();  

 

#pragma warn Directive

in case there are some warning and you are sure it works as your expection and there is no any risk, you can use #pragma warn to disable it, but the code shall have a well document. 

#pragma warn +xxx (To show the warning)
#pragma warn -xxx (To hide the warning)
#pragma warn .xxx (To toggle between hide and show)

• #pragma warn -rvl: This directive hides those warning which are raised when a function which is supposed to return a value does not return a value.
• #pragma warn -par: This directive hides those warning which are raised when a function does not uses the parameters passed to it.
• #pragma warn -rch: This directive hides those warning which are raised when a code is unreachable. For example: any code written after the return statement in a function is unreachable.