Path: utzoo!utgpu!news-server.csri.toronto.edu!clyde.concordia.ca!ccu.umanitoba.ca!salomon
From: salomon@ccu.umanitoba.ca (Dan Salomon)
Newsgroups: comp.lang.c
Subject: Re: confusion with char *a and char a[NUM]
Message-ID: <1990Dec4.214845.18949@ccu.umanitoba.ca>
Date: 4 Dec 90 21:48:45 GMT
References: <7656@umd5.umd.edu>
Distribution: na
Organization: University of Manitoba, Winnipeg, Canada
Lines: 28

In article <7656@umd5.umd.edu> jjk@astro.umd.edu( Jim Klavetter) writes:
>
>I can have two identical files except that one I declare a to be
>	char a[NUM]
>and the other has
>	char *a with a malloc of NUM+1 characters.
>
   ...
>However, if I have
>	a=strchr(string, ":");
>I get the error message
>	121: incompatible types in assignment
>

No big mystery.
    char a[NUM];
declares "a" to be a constant pointer to an array of char that points
to the region allocated by the compiler.
Hence you cannot change its value.
    char *a;
declares a to be a variable pointer to an array of char.
This treatment allows the optimization of array accesses with
constant subscripts.
-- 

Dan Salomon -- salomon@ccu.UManitoba.CA
               Dept. of Computer Science / University of Manitoba
	       Winnipeg, Manitoba, Canada  R3T 2N2 / (204) 275-6682


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