Welcome to OGeek Q&A Community for programmer and developer-Open, Learning and Share
Welcome To Ask or Share your Answers For Others

Categories

0 votes
224 views
in Technique[技术] by (71.8m points)

c - Malloc a struct at a specific point in memory?

I'm trying to create a struct at a specific location in memory:

struct inRAM *ptr = (struct inRAM*)malloc(sizeof(struct inRAM));

But this line only allocates the memory at a place in RAM that is not retainable. I need to malloc beginning at a specific memory address for it to work properly, but how?

See Question&Answers more detail:os

与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…
Welcome To Ask or Share your Answers For Others

1 Reply

0 votes
by (71.8m points)

For embedded systems where you need to access specific memory addresses for I/O, you normally write directly to the address.

You don't need to malloc here, that's used to manage blocks of memory or structures where you don't care where it will be located.

e.g. to write to address c00010

ptr = c00010;
ptr->field = value;

Also, when using structures overlayed onto memory be careful about padding and structure alignment.


与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…
OGeek|极客中国-欢迎来到极客的世界,一个免费开放的程序员编程交流平台!开放,进步,分享!让技术改变生活,让极客改变未来! Welcome to OGeek Q&A Community for programmer and developer-Open, Learning and Share
Click Here to Ask a Question

...