On Tue, Nov 10, 2009 at 08:03:26AM -0800, Nate Eldredge wrote: > On Tue, 10 Nov 2009, Alexander Best wrote: > > >ps: would be nice if strcasecmp could protect itself from segfault with > >one or > >both of the args being NULL. > > I disagree. What do you think it should do instead? Return 0? If it > did, would you have found your bug? > > The same argument could be made for any of the string.h functions, but I > don't think it actually holds water. Such checks add overhead, and only > provide an illusion of safety. Sure, strcasecmp could avoid causing the > segfault itself, but at the cost of letting a broken program continue and > possibly cause more damage. It could call abort(), but then you'd just > have the same result (program terminates) with a different signal, and > doing your check in software rather than letting the MMU hardware do it. > It could print a message, but that pollutes the program's output, and 15 > seconds debugging the core dump will reveal the problem anyway. > > Having a library function "protect itself" in this manner is not actually > helpful, IMHO.
I remember System V to actually map zero page at 0, thus causing all string functions to behave like it was supplied empty string when argument is NULL. I believe Solaris still provides the library that could be LD_PRELOADed for the same effect.
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