DougGwyn

It has been many years since a C++-to-C preprocessor has been commonplace. There's just too much new stuff in recent C++ to map it all easily into straight C.

Since I do almost all my software development in a Unix environment, usually I check the toolbox to see if there is already a program that has nearly the functionality I want, and if so then I cobble together a shell script. Sometimes (as with the Sudoku solver) it will be necessary to build a new component, and for that I usually use C since I am comfortable and experienced with it. (Also, if coded in Standard C, odds are that I can install it on whatever platform I need, with little or no adaptation.)

I'm not sure what your requirement is. Usually things work out if you're careful not to assume any specific value for alignment etc. It may mean a few unused bytes here and there, but keeping things simple and portable often pays off.

Okay, check my About text. I'll soon remove it, to avoid getting a lot of spam.

You should be commended for the fast customer service!

There is no grand goal that I know of. I wish more importance were being placed on keeping existing well-written code working, which includes continued support for what might be considered near-obsolete. If one wanted to design a new (not fully compatible) language, that could have lofty goals; just don't call it "C".

Try explaining the concept of "scope", starting with nested blocks. It does require some practice. I suggest not unnecessarily reusing identifiers associated with different objects.

The problem is that if the checks are always performed, the object code is significantly slowed down. If all computers supported the checking in hardware, then we could do it. You don't really want the current C approach (signal) to trigger except in an emergency, because there is no way to insert cleanup/retry/etc. recovery code via a signal handler.

I tried, but two spaces yielded what you saw.

Try using "lint" or other code checkers.

Everybody seems to draw pictures of the raw memory (word-oriented) data.

UTF-8 encoding works "as is" based on byte strings (char[]). The latest versions of the draft standard provide somewhat more support.

I recommend heading toward a future where only UTF-8 encoding is used for multibyte characters and UCS-2 or similar for wchar_t. There is no need to support several different encodings.

One possibility is to modify some existing program to include an additional new feature. You should soon develop a sense for what works well versus what causes problems.

Many uses of strchr do write via a pointer derived from a non-const declaration. When we introduced const qualifier it was noted that they were actually declaring read-only access, not unchangeability. The alternative was tried experimentally and the consequent "const poisoning" got in the way.

Actually there was no need to disenfranchise non-twos-complement architectures. Now that SIMH has a CDC-1700 emulation, I had planned on producing a C system for it as an example for students who have never seen such a model.

We would need a specific proposal and assurance that nearly all computers can efficiently provide that service. It is more likely in the POSIX standard.

How about a Sudoku solver? Send me a request via e-mail.

There are deficiencies in almost all proposals. Two new functions which avoid the problems are supposed to be published in C202x: strcasecmp and strncasecmp, added in header strings.h (note: not string.h).

What removal? C11 section 6.7.6.2 specifies the semantics.

In BRL's MUVES project, we used a 2-character prefix indicating category. E.g., all the external identifiers for our fancy memory allocator began with "Mm", where Mm.h documented the interface for the Mm package only.

To minimize the external identifiers, one could make just the name of a container structure the sole entry access handle, with structure members pointing to the functions. Then use it like:

  #include <Mm.h>
  if ((new = Mm.allo(size)) == NULL)
    Er.abort("out of memory");

It all depends on how organized previous workers were, and what your goal is for a modification of the source text. Often, headers (dot-h files) document the data structures and interfaces.

Okay, is there a starting thread for today's C Experts panel? I miss the old net newsgroups.

Some simple instructions about how to use a thread for conversation would be appreciated. Thanks!

If you find SIMH, look for a "software" folder nearby, which contains several operating systems. Some of them, like Unix, may be tricky to install unless you have an installer's guide. BitSavers.org is a good site for documentation and several items of system software.