From mboxrd@z Thu Jan  1 00:00:00 1970
Message-ID: <fcd77367f7f9cb9251f0f23c50cf2e83@mail.gmx.net>
To: 9fans@cse.psu.edu
Subject: Re: [9fans] memory woes
From: sretzki@gmx.de
Date: Fri,  5 Jan 2007 15:51:22 +0100
In-Reply-To: <687643a97ce7ba1e1f4c5ab24eeb5959@coraid.com>
MIME-Version: 1.0
Content-Type: text/plain; charset="US-ASCII"
Content-Transfer-Encoding: 7bit
Topicbox-Message-UUID: fdf07a94-ead1-11e9-9d60-3106f5b1d025

> you are forgetting +1 for the null.  you need strlen("Hello World")+1.

Heh! Yeah, true. But then the strcpy() would write into non-allocated area, so why does the free()-call make it crash?

>
> - erik
>
>> #include <u.h>
>> #include <libc.h>
>>
>>
>> void main(int argc, char **argv) {
>> 	int i;
>> 	char *m00;
>>
>> 	for(i=0; i<=5; i++) {
>> 		if((m00 = malloc(strlen("Hello World"))) == nil) {
>> 			print("drama! [%d]\n",i);
>> 			exits("malloc");
>> 		}
>> 		strcpy(m00,"Hello World");
>> 		print("%d> %s\n",i,m00);
>> 		free(m00);
>> 	}
>> 	exits(nil);
>> }