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
488 views
in Technique[技术] by (71.8m points)

c - single bit manipulation

is it possible to get just one bit of an int in C and then flip it without reading the entire int and writing it back to memory?

context: trying to avoid too many locks/unlocks in pthread.

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)

You can not read a single bit from the memory, actually you can not force CPU to read only a single byte. It is always reading a full cache line, which could have different sizes for different CPUs.

But from the language point of view you can use bit fields http://publications.gbdirect.co.uk/c_book/chapter6/bitfields.html


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

...