system() question

[Jonathan I. Kamens]

In article <9321 at hub.ucsb.edu>, 6600bori at ucsbuxa.ucsb.edu (Boris Burtin) writes:
|> Can anyone tell me why I get a core dump
|> when I try to do :
|> 
|>  system("last [username] > ~/filename");

  I have no idea why you get a coredump, and there's no way really for us to
tell.  Have you attempted to analyze the coredump with a debugger to see what
it's from?  Is it your process coredumping, or is it the shell that's being
started?  I don't get a coredump on my machine.  What type of machine are you
using, running what version of Unix?

  In any case, I suspect that at least part of the problem is that the bourne
shell, which is what system uses, doesn't understand "~".  Change the "~" to
"$HOME".  Observe:

	1 -> extern int system(char *);
	2 -> system("last jik > ~/lastjik");
	Linking from '/lib/libc.a' ... Linking completed.
	sh: ~/lastjik: cannot create
	(int) 256
	3 -> system("last jik > $HOME/lastjik");
	(int) 0

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