Define static function header file

Add a comment. Active Oldest Votes. Improve this answer. Well, the compiler will probably inline short functions. So it could actually use less memory, if the function is short enough. But I would prepend an "inline", so you don't get compile warnings about unused static functions. Better late, I hope. I wonder if the linker will optimize that out. It sees addTwo on b. Still bigger than size of the function , but not as bad? Compared to having a single shared definition which is called by many users, that wastes memory.

RBerteig RBerteig Perhaps the function contains static variables that preserve their value between calls internal state , and thus each module gets "its own private copy" of the vars by having its own clone of the function? I'd personally avoid it because it would provide too many chances for a clever optimizer or code maintainer to break it by "cleverly" eliminating the apparently redundant function bodies.

Also, it provides exactly one set of internal state per translation unit. It would be less confusing and less fragile to put all of the state in an explicit state variable, passed in to each call. Yeah, I don't agree with that 'design' either. Although the pro is that the private data is encapsulated, visible right where needed and nowhere else. So saying that the only difference will be performance and code size is wrong. There is a strong semantic difference if the function contains a static local variable.

In one case, the static variable will be shared, in the other case there will be multiple different static variables for each compilation unit. Therefore the function behavior may be totally different.

Static variable has file scope. Say I have two following files: file1. I am unable to understand this behavior. Can any body explain how scope and linkage are working in this scenario. Improve this question. Vikram Ranabhatt Vikram Ranabhatt 6, 15 15 gold badges 64 64 silver badges bronze badges.

Related, see Do not define an unnamed namespace in a header file — jww. Add a comment. Active Oldest Votes. Improve this answer. After preprocessing, this: include "file1. My thiniking was there will be two compilation unit.

Thanks for clearing by doubts — Vikram Ranabhatt. Mahesh Mahesh Sign up or log in Sign up using Google. Sign up or log in Sign up using Google. Sign up using Facebook.

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Visit chat. Linked 0. Related Hot Network Questions. Question feed. Personally, I do recommend writing a couple of test programs using the non-inlined functions first, and compare the performance and results to the inlined versions. Comparing the results ensure the inlined versions do not have bugs off by one type is common here!

Why would you want a both global and static function? In c, functions are global by default. You only use static functions if you want to limit the access to a function to the file they are declared. So you actively restrict access by declaring it static Stack Overflow for Teams — Collaborate and share knowledge with a private group.

Create a free Team What is Teams? Collectives on Stack Overflow. Learn more. Static functions declared in "C" header files Ask Question. Asked 4 years, 11 months ago. Active 2 years, 5 months ago. Viewed 48k times. For me it's a rule to define and declare static functions inside source files, I mean. My questions are: What is the problem of declaring static functions in header files?

What are the risks? What the impact in compilation time? Is there any risk in runtime? Improve this question. Daniel 9, 12 12 gold badges 37 37 silver badges 74 74 bronze badges. I would rather ask: What could be an acceptable reason to do that? IMO it's definitely code smell. Small static inline functions are occasionally used as accessor functions into structure data types, as a better replacement for preprocessor macros.

Unlike macros, static inline functions provide compile time type checking, and can refer to their parameters multiple times which is problematic with preprocessor macros.

NominalAnimal Good point. Seeing the source code allows the compiler to perform better optimizations in general inlining being one of them without linker help.