A "printf" in "printf"

In the event of a “printf” in a “printf”, what will the terminal print out?

/*
Author: luckyshq
Date:2013-10-27
*/

#include<stdio.h>

int main()
{
    printf("%d", printf("%d", 1234));
    return 0;
}

From:http://www.cplusplus.com/reference/cstdio/printf/

We can see:

function

printf

int printf ( const char * format, … );

Print formatted data to stdout

Writes the C string pointed byformat to the standard output (stdout). Ifformat includesformat specifiers (subsequences beginning with %), the additional arguments followingformat are formatted and inserted in the resulting string replacing their respective specifiers.

Return Value

On success, the total number of characters written is returned.

If a writing error occurs, the error indicator (ferror) is set and a negative number is returned.

If a multibyte character encoding error occurs while writing wide characters, errno is set to EILSEQ and a negative number is returned.

So, the first printf will print the total number of characters(of 1234) —– 4