Is Recursively Calling `main()` in C Allowed?

Can main() Be Called Recursively in C ?

The code snippet below demonstrates the curious behavior of calling main() recursively in C .

<code class="cpp">#include <iostream>
#include <cstdlib>

int main() {
    std::cout << "!!!Hello World!!!" << std::endl;
    system("pause");
    return main();
}</code>

The code compiles successfully, and when executed, it displays "Hello World!!!" indefinitely. However, it is important to note that this behavior is not standard-compliant in C . The C Standard explicitly forbids calling main() recursively or taking its address.

In practice, however, some compilers, such as the Linux g compiler, allow main() to be called in main(). This permissiveness is evident in the following code:

<code class="cpp">#include <cstdlib>
#include <iostream>
using namespace std;
int main()
{
    int y = rand() % 10;
    cout << "y = " << y << endl;
    return (y == 7) ? 0 : main();
}</code>

When executed, this code generates a series of "y" values (e.g., 3, 6, 7), each from a subsequent call to main().

Analyzing the compiled assembly reveals that main() is called just like any other function:

<code class="assembly">main:
...
cmpl    , -12(%rbp)
je      .L7
call    main
...
.L7:
...
leave
ret</code>

Despite the Standard's prohibition, g seems to tolerate such calls. However, this behavior is not guaranteed, and programmers should avoid relying on it to ensure portability and compliance with the C Standard.

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