about macro definition

[hpsoar]

Now I'm reading a book, which annotated the sgi stl. And I found the
names of macros often starts with two underline, such as
__STL_CONFIG_H, I wonder why so, and why not start with only one like
_STL_CONFIG_H

 

[Alf P. Steinbach]

* hpsoar:

Now I'm reading a book, which annotated the sgi stl. And I found the
names of macros often starts with two underline, such as
__STL_CONFIG_H, I wonder why so, and why not start with only one like
_STL_CONFIG_H

Both forms are reserved to the implementation (of standard library), so it
doesn't matter. It's just a choice they made for whatever reason. An ordinary
C++ program or library should *never* use such reserved name forms, so,
absolutely do not emulate what they do, because that code operatoes under very
different conditions and rules than your code does.


Cheers & hth.,

- Alf

 

[hpsoar]

* hpsoar:


Both forms are reserved to the implementation (of standard library), so it
doesn't matter. It's just a choice they made for whatever reason. An ordinary
C++ program or library should *never* use such reserved name forms, so,
absolutely do not emulate what they do, because that code operatoes under very
different conditions and rules than your code does.

Cheers & hth.,

- Alf

thanks