Re: "A diagram of C23 basic types"

scott@slp53.sl.home (Scott Lurndal) writes:

Tim Rentsch <tr.17687@z991.linuxsc.com> writes:
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antispam@fricas.org (Waldek Hebisch) writes:

>
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I believe that's not true, but certainly it is not /clearly/ true.
A lot of time passed between 1978, when K&R was published, and
1989, when the first C standard was ratified.  No doubt the C
standard unified different practices among many existing C
implementations, but it is highly likely that some of them
anticipated the rules that would be ratified in the C standard.

>
Looking at SVID 3rd edition (1989), size_t did not yet exist, so in
that particular case, there was no need to implicitly define it in
any header file.
>
For interfaces that require custom typedefs (for example, stat(2)),
the SVID requires the programmer include <sys/types.h> before
including <sys/stat.h>.
>
When size_t was added there were existing interfaces where the
argument was changed to require size_t/ssize_t.  These interfaces
did not, at the time, require the programmer to include
<sys/types.h> or <stddef.h> in order to use the interface, for
example in the SVID memory(BA_LIB) interface description, the
programmer had been instructed that only <string.h> was required
for the str* functions, and <memory.h> was required for the mem*
functions - but the SVID noted at that time that the latter was
deprecated - the pending ANSI C standard was to require only
<string.h>.
>
So, when the arguments of memcpy/strcpy were changed from int to
size_t, they couldn't go back and require existing code to include
e.g. <stddef.h> to get size_t;  POSIX chose to note in the
interface description that additional typedefs may be visible
when <string.h> is included.
>
  "The <string.h> header shall define NULL and size_t as described
   in <stddef.h>."

Thank you for this report.  I wasn't paying attention to any
standardization efforts in that time frame;  it's good to have
some actual data to look at.

After digging into the history, I have the impression that SVID
was hoping to be a leader in defining standard interfaces (which
I think included C proper but was not limited to that, which
makes sense as there was also Unix to consider).  So it isn't
surprising that size_t did not appear in SVID until the onoing
ANSI effort completed, and the ANSI C standard was ratified.  No
doubt there were other organizations closer to the then-current
C standardization effort (which had been going on for at least
five years IIANM), and it seems likely that in some cases there
were environments in use that anticipated the looming ANSI C
standard.