The three types of in l in in g behave similarly in two important c ases: when the in l in e keyword is used on a stati c fun c tion, like the example above, and when a fun c tion is first de c lared without us in g the in l in e keyword and then is def in ed with in l in e , like …. In l in e fun c tion is a fun c tion that is expanded in l in e when it is c alled. When the in l in e fun c tion is c alled whole c ode of the in l in e fun c tion gets in serted or substituted at the po in t of in l in e fun c tion c all.
Posted: 5 days ago An in l in e fun c tion may have multiple def in itions. This is important when you def in e a fun c tion in side a header file. Usually, you de c lare fun c tions in a header and implement it in a. Other c ompilation units in c lude the de c laration in the header and are …. The way to use it is to put a fun c tion def in ition in a header file with these keywords, and put another c opy of the def in ition la c k in g in l in e and extern in a library file.
The def in ition in the header file will c ause most c alls to the fun c tion to be in l in e d. Posted: 1 week ago A fun c tion c onta in in g a loop. If the fun c tion is re c ursive. If there are stati c variables present in the fun c tion. If there is a swit c h or goto statement in the fun c tion. If a return statement exists in the fun c tion. The rest of the functions in are not even considered for coverage marked as "-:" in the. The function on line is not tested, the function on line is covered by a unit test.
The resulting coverage report correctly shows the lines from the covered function as covered does not show that the lines for the uncovered function are not covered. It seems that the compiler optimizes unused static functions even in optimization level -O0. If the static function defined in the same definition is called by different compilation units, each compilation unit has its own copy, which is only visible to the corresponding compilation unit.
The function of inline is external linkage. The above differences directly lead to: if there is a static variable in the function, for the inline function, this variable is shared for different compilation units Meyer's Singleton ; for the static function, this variable is not shared. Look at the code below to see the difference. Specify inline Don't put inline and compiler optimization on the hook any more. Without inline, small function compilers will also optimize automatically.
No stand-alone object code is emitted, so this definition can't be called from another translation unit. You can 1 have a separate not inline definition in another translation unit, and the compiler might choose either that or the inline definition. Such functions may not contain modifiable static variables, and may not refer to static variables or functions elsewhere in the source file where they are declared.
In this example, all the declarations and definitions use inline but not extern :. The function won't be callable from other files; if another file has a definition that might be used instead. It says that the inline definition does not forbid an external definition elsewhere, but then that it provides an alternative to an external definition.
Unfortunately this doesn't really make clear whether this external definition must actually exist. In practice unless you are torture-testing your compiler it will exist: if you wanted to keep your inline function entirely private to one translation unit, you make it static inline.
A function where at least one declaration mentions inline , but where some declaration doesn't mention inline or does mention extern. Stand-alone object code is emitted just like a normal function and can be called from other translation units in your program. In this example all the declarations and definitions use inline but one adds extern :. A function defined static inline.
A local definition may be emitted if required. You can have multiple definitions in your program, in different translation units, and it will still work. Just dropping the inline reduces the program to a portable one again, all other things being equal.
This is probably useful primarily for small functions that you might otherwise use macros for. If the function isn't always inlined then you get duplicate copies of the object code, with the problems described above.
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