On Tue, 2 Sep 2014, Joey Ye wrote: > Apparently newlib is not following this specification very well, as > there are symbols like _abc_r defined every where in current newlib. I > am not implying the spec should not be followed, but is newlib > designed to have a loose spec for the single underscore?
Identifiers beginning with a single underscore are reserved with file scope. This means an application cannot provide an external definition of them, because such an external definition would have file scope. So it's fine for the implementation to define such identifiers and use them in the implementation of standard functions. You do still need to be more careful with them than with _[_A-Z]* identifiers. For example, you can't do #define standard_function(x) _standard_function(x) in your libc headers, because the user's application could legitimately define a variable called _standard_function at block scope, then try to call standard_function within that block. So in general it's safer to use the double underscore in the implementation, unless there is some clear reason to use the single underscore. -- Joseph S. Myers jos...@codesourcery.com _______________________________________________ AVR-libc-dev mailing list AVR-libc-dev@nongnu.org https://lists.nongnu.org/mailman/listinfo/avr-libc-dev
