Hello.
To prevent header files from being included more than once in the same
translation unit, we use include guards like
# ifndef FOO_H
# define FOO_H
...
# endif
Recently I came to know that I can use simply:
# pragma once
instead of the above group of sentences and the desired effect is still
accomplished.
This leads me to think of two things:
1. why use the ifndef-define-endif method when the pragma once method is
simpler and cleaner?
2. why should we need to use either method at all? If it is a
universally undesirable behaviour that the same header file is included
in a translation unit more than once, then an intelligent compiler (or
preprocessor) itself can by default take of this, right?
I understand that to write portable code that compiles on
not-so-intelligent compilers, we may need to do something manually, so
question 2 is answered, but question 1 still stands...
Shriramana Sharma.
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