fread获取存储在堆栈中的什么位置?

I have a small doubt, i'm doing a ctf that provides me only the ELF file. I have been able, using Ghidra to decompile it, but here is the problem: at a certain point i read: fread(flag,0x400,1,__stream); (before there was : __stream = fopen("./flag","rb");

1)我认为fread中的“标志”是fread存储从flag.txt中读取“ __stream”的内容的地方,但是以前从未声明过(我指的是fread中的“ flag”),是吗实际上是我所期望的缓冲区?如果是,则将读取的值存储在内存中的什么位置(那么该缓冲区存储在哪里?在堆栈中?)

2)fread具有0x400尺寸值和1作为要读取的元素数是正常的吗?

预先感谢大家!