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Are nested functions a bad thing in gcc ?
As far as I know, C does not allow a function to be defined within other function. But the following code compiles and runs without any error in gcc. Can someone explain the reason why? See this also : http://ideone.com/AazVK
#include <stdio.h>
void val1( int x )
{
void sig( int x ) {
printf("%d\n",x*10);
}
sig(x);
}
int main()
{
void val2(int x) {
x = x*10;
val1(x);
printf( "%d\n", x );
if ( x < 10000 ) {
val2(x);
}
}
val2(20);
return 0;
}
858
asked Jan 16 '11 13:01
Nested function is not supported by C because we cannot define a function within another function in C. We can declare a function inside a function, but it's not a nested function.
A function which is defined inside another function is known as inner function or nested functio n. Nested functions are able to access variables of the enclosing scope. Inner functions are used so that they can be protected from everything happening outside the function. This process is also known as Encapsulation .
A nested function is a function defined inside the definition of another function. It can be defined wherever a variable declaration is permitted, which allows nested functions within nested functions. Within the containing function, the nested function can be declared prior to being defined by using the auto keyword.
Using a function as one of the arguments in a formula that uses a function is called nesting, and we'll refer to that function as a nested function.
gcc (but not g++) supports nested functions as a C language extension.
107
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