c - 解释一下下面的输出？

Question

#include<stdio.h>
void main()
{
    char ch;
    if((ch=printf(1234))
        printf("A");
    else
        printf("B");
}

答案是B:但我不知道 ch 被赋予了什么值以及 printf(1234) 会发生什么

Answer 1

来自 printf(3) 手册页:

Return value
   Upon successful return, these functions return the number of characters
   printed  (not  including  the  trailing  '\0'  used  to  end  output to
   strings).