From mboxrd@z Thu Jan  1 00:00:00 1970
From: ron@ronnatalie.com (Ron Natalie)
Date: Thu, 11 May 2017 18:41:47 -0400
Subject: [TUHS] C declarations.
In-Reply-To: <20170511223232.GM4341@mcvoy.com>
References: <015401d2caa0$79762650$6c6272f0$@ronnatalie.com>
 <68E8DC0A-D1B8-4FF0-AD26-ACDC57E308AF@pobox.com>
 <20170511223232.GM4341@mcvoy.com>
Message-ID: <015b01d2caa7$c658c020$530a4060$@ronnatalie.com>


>  I'm curious as to what is busted about arrays in C?  To me they just
seemed like a way to define how to look at a wad of memory and they seem to
work for me.  

The problem is they don't work like every other type.    Somewhere around
the phototypesetter release or V7, they fixed structs to be
assignable/passable to functions.
They didn't do that for arrays.   They retained their half-assed
quasipointer status.    It would have been easy to bite the bullet back in
those days before people codified the inane behavior.

For example:

struct foo {
    int a;
    int b;
};

struct foo x;
x.a = 1;
x.b = 1;
struct foo y;
y = x; // works fine.

struct foo myfunc(struct foo arg) {
    arg.a = 5;
    return 5;
}
y = myfunc(x);   // does not modify x


Now look at arrays:

char x[4] = { 1, 2, 3, 4};

char y[4];
y = x ; // illegal

void myfunc(char arg[4]) {
    arg[0] = 1000;
}

myfunc(x);  // CHANGES X!

If had my way, y = x and passing and returning arrays by value would work
just like every other C type.