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From: schlake@nmt.edu (William Colburn)
Newsgroups: comp.lang.c
Subject: Re: stupid compilers
Message-ID: <1990Aug31.214133.25530@nmt.edu>
Date: 31 Aug 90 21:41:33 GMT
References: <163@prodix.liu.se>
Organization: New Mexico Institute of Mining and Technology
Lines: 50

In article <163@prodix.liu.se> martin@prodix.liu.se (Martin Wendel) writes:
>
>Can anyone explain to me why this piece of code is OK to run:
>
>           #include <stdio.h>
>           #include <strings.h>
>           main()
>           {
>             char line[];
>             char *tmp = "1234";
>             strcpy(line, tmp);
>             printf("%s\n", line);
>           }
>
>when this produce a segmentation fault:
>
>           #include <stdio.h>
>           #include <strings.h>
>           main()
>           {
>             char *line;
>             char *tmp = "1234";
>             strcpy(line, tmp);
>             printf("%s\n", line);
>           }
>

It seems to me that they should BOTH fail.  You are copying a string to a
pointer, and not having the pointer point anyplace.  The fact that the first
program works is pure luck.

#include <stdio.h>
#include <strings.h>

char *malloc();
int strlen();

main()
{
  char *line;
  char *tmp = "1234";
  int strsize;

  strsize=strlen(tmp);
  line=malloc(strsize+1);
  strcpy(line,tmp);
  printf("%s\n",line);
}

							Schlake