Inline Functions in C++

================
non-inline functions
================
 
For non-inline functions, if the prototype does not change, often the files that use the function need not be recompiled.
 
lib.cpp
 

#include <stdio.h>

void show(int i) {
  printf("show %d using style 1
", i);
}

 
main.cpp

void show(int i);

int main(int argc, const char *argv[]) {
  show(100); 
  return 0;
}

$ g++ -c -fPIC lib.cpp
$ g++ -fPIC -shared -Wl,-soname,libref.so -o libref.so lib.o
$ g++ -c main.cpp
$ g++ -o main main.o -lref -L.
$./main
show 100 using style 1
Change 
printf("show %d using style 1", i); to
printf("show %d using style 2", i);
$ g++ -c -fPIC lib.cpp
$ g++ -fPIC -shared -Wl,-soname,libref.so -o libref.so lib.o
$ ./main
show 100 using style 2
 
================
inline functions
================
lib.h

#include <stdio.h>

inline void show(int i) {
  printf("show %d using style 1
", i);
}

 caller1.cpp

#include "lib.h"

void call1() {
  show(100);
}

 caller2.cpp

#include "lib.h"

void call2() {
  show(100);
}

 main.cpp

xtern void call1();
extern void call2();
int main() {
  call2();
  call1();
}

$ g++ -c *.cpp
$ g++ -o main *.o
$ ./main
show 100 using style 1
show 100 using style 1
Now change 
printf("show %d using style 1", i); to
printf("show %d using style 2", i);
For the following commands:
$ g++ -c caller1.cpp
$ g++ -o main *.o
$ ./main
The result is
show 100 using style 2
show 100 using style 2
 
For the following commands:
$ g++ -c caller2.cpp
$ g++ -o main *.o
$ ./main
The result is
show 100 using style 1
show 100 using style 1