> > From: Thomas Monjalon [mailto:tho...@monjalon.net] > > > > 10/06/2024 18:31, Konstantin Ananyev: > > > Morten said: > > > > The coding style guide says: > > > > > > > > "Variables should be declared at the start of a block of code rather > > > > than > > in the middle. The exception to this is when the variable is > > > > const in which case the declaration must be at the point of first > > use/assignment. Declaring variable inside a for loop is OK." > > > > > > > > Since DPDK switched to C11, variables can be declared where they are > > > > used, > > which reduces the risk of using effectively uninitialized > > > > variables. "Effectively uninitialized" means initialized to 0 or NULL > > where declared, to silence any compiler warnings about the use of > > > > uninitialized variables. > > > > > > > > Can we please agree to remove the recommendation/requirement to declare > > variables at the start of a block of code? > > > > > > I know that modern C standards allow to define variable in the middle. > > > But I am strongly opposed to allow that in DPDK coding style. > > > Such practice makes code much harder to read and understand (at least for > > me). > > > > Yes it is convenient to know that all variables are described > > in a known place, just after function parameters. > > > > There is also a consistency concern. > > > > Old contributors like to be in a comfort zone, > > and we don't want to lose old contributors. > > New contributors may be refrained by old rules, > > and we would like to get more new contributors. > > > > So that's a tricky decision. > > > > Independent research shows that readability is improved by declaring local > variables as close as possible to their first use: > https://barrgroup.com/72-initialization#footnote12
Hmm... seems they don't provide any data to back up their statements. Specially that one sounds weird for me: " Too many programmers assume the C run-time will watch out for them, e.g., by zeroing the value of uninitialized variables on system startup." Why on earth people would assume that? And what exactly means 'too many? 1%? 10%? 90%? > > Old people (like myself) need to unlearn their bad old habits (originating > from limitations in old C standards), and embrace modern > methods to reduce the risk of introducing bugs. Allowing to define variables in the middle of the code by itself wouldn't prevent of use of un-initialized variables. From other side - compilers are quite good these days to catch such bugs. So I don't think it is a completing argument..
