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Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!csd4.milw.wisc.edu!leah!rpi!weber.cs.rpi.edu!mcintyrd
From: mcintyrd@cs.rpi.edu (David McIntyre)
Newsgroups: comp.unix.questions,comp.unix.wizards
Subject: Re: system() --- the C function from hell?
Keywords: system, unix, question, does anyone use this line?
Message-ID: <2349@rpi.edu>
Date: 30 Apr 89 11:45:44 GMT
References: <1827@uop.edu>
Sender: usenet@rpi.edu
Organization: Rensselaer Polytechnic Institute, Troy, NY
Lines: 32

In article <1827@uop.edu> jeff@uop.edu (Jeff Ferguson) writes:
>	The system() call seems to wreak havoc with integer variables.
>I have the following code:
>
>int lowp, hip;
>...
>scanf("%d", &hip);
>scanf("%d", &lowp);
>sprintf(str, "/bin/mkdir directory");
>system(str);
>...
>
>I printed the values of LOWP and HIP before the system() call, and
>everthing was pee-chee (like the folder).  I print them out after
>the call and the values have been blown to high Heaven: before they
>were both 3, while after system(str) they are in the tens of millions.

I would suggest that str is a (char *) variable that has not
had any space allocated for it, and it is overwriting the
two integers somehow.  You should either make str something like

char str[20];

or malloc it, something like this:

	str = (char *)malloc(20*sizeof(char));


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