Op 23 apr 2008, om 08:50 heeft Mike Meyer het volgende geschreven:
On Tue, 22 Apr 2008 22:40:21 -0700
"Garrett Cooper" <[EMAIL PROTECTED]> wrote:

Hi all,
I made an oops in a program, which uncovered "feature" in strdup(2) that I wasn't aware of before. So I was wondering, is strdup(pointer = NULL)
supposed to segfault should this just return NULL and set errno?

Yes, it's supposed to segfault. Check out what, say, strcpy does if
you ask it to copy a NULL pointer. And this is an improvement from the
bad old days, when they would happily walk through memory starting at
0.....

I don't like it this way. I would like:

strdup(NULL) = NULL
strdup(string) = copy of string

strcpy(NULL, NULL) = NULL
strcpy(s1, NULL) = ERROR
strcpy(NULL, s2) = NULL (with s2 unchanged)
strcpy(s1, s2) = normal

But I am not sure of the implications. Maybe in some situation it is bad... Anyone?


Besides, errno is used to signal errors from system calls. strdup
isn't a system call, it's a library function (says so at the top of
the man page).

But strdup uses malloc, which is a system call (from the strdup manual: If insufficient memory is available, NULL is returned and errno is set to ENOMEM.)

Regards,
        Bernard

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