Is it possible to find out when the current syntax of strcpy was added to the C standard?

问题

The oldest publicly available C standard seems to be the ISO/IEC 9899:1999, published in 1999. There the strcpy function already has its current syntax.

The reason I ask it is that I found a really, really old system where (to my greatest shock) strcpy seems to have almost the same syntax as memcpy.

In that implementiation strcpy behaves like this:

strcpy(char *destination, char *source, int length) works just like the modern memcpy
strcpy(char *destination, char *source) does compile, but it doesn't have any noticeable side-effect, just as if it was called with length = 0.
strncpy works exactly just like strcpy, it even compiles with just 2 parameters.

So, for someone interested in C-archeology (and having access to very old standards), was there a C standard where strcpy was not defined? Which was the first standard where it was defined? Am I dealing with a non-standard conforming compiler (a compiler that doesn't even conform to the oldest C standard)?

Edit: If this source is to be trusted, strcpy was already defined in its current form already in 1989. So I have to deal with something even older than I first suspected!

回答1:

The first published standard for C was C89 (ANSI X3.159-1989). It defined strcpy as follows:

char *strcpy(char *s1, const char *s2);

Before, that, try looking for the first version of "The C Programming Language" by Kernighan and Ritchie, which was the de facto standard from its publication in 1978 to 1989. I would not be surprised if strcpy predates this.

According to http://cm.bell-labs.com/7thEdMan/, Version 7 UNIX, released in 1979, defined strcpy as

char *strcpy(s1, s2)
char *s1, *s2;

I wasn't able to find strcpy in the documentation for Version 6 UNIX, which was released in 1975, but its "C Manual", written by Dennis Ritchie, contained an example function

copy(s1, s2)
char *s1, *s2
{
    while(*s2++ = *s1++);
}

Its "C Tutorial", written by Brian Kernighan, instead contained this version:

strcopy(s1, s2)
char s1[ ], s2[ ]; {
    int i;
    for( i = 0; (s2[i] = s1[i]) != '\0'; i++ );
}

This suggests that the modern version of strcpy originated somewhere between the release of V6 UNIX in 1975 and the publication of K&R C in 1978.

Notice that even at this early time, we already see stylistic differences between the two principle authors of C: Kernighan put the opening bracket of functions on the same line as the parameter declaration, while Ritchie preferred to put it on a new line by itself.

回答2:

strcpy is defined in K&R C dating to 1978.

Here it is, p88:

/* strcpy: copy t to s; pointer version */ 
void strcpy(char *s, char *t)
{
   int i;
   i = 0;
   while ((*s = *t) != '\0') {
      s++;
      t++; 
   }
}

Or, as reduced in the text of the greatest programming book ever written:

/* strcpy: copy t to s; pointer version 3 */ 
void strcpy(char *s, char *t)
{
       while (*s++ = *t++)
           ;
}

来源：https://stackoverflow.com/questions/25300040/is-it-possible-to-find-out-when-the-current-syntax-of-strcpy-was-added-to-the-c

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