csh prompt setting within a c-program

[David Connet]

How do I set a csh prompt from witn a c-program?
I'm trying to do is:
	strcpy(ps1,"PS1=new prompt: ");
	if (putenv(ps1))
		fprintf(stderr,"%s: Environment not set up correctly.\n",pgmname);
	system(shell);

This works under sh and ksh.  But not csh.
Can anyone help?

Thanks in advance.

Dave Connet
connet at castor.usc.edu

PS: Please reply via email as I don't read this group.