Re: Segmentation fault
davidturetsky@email.msn.com (davidturetsky) wrote:
>I see from further investigation that gcc wants me to be more actively
>concerned with memory management than was required under Visual C, and I was
>logging on to apologize for bothering the list. I posted because this code
>ran cleanly under Visual C, so I thought I ran into a Linux nuance
>
>It looks as though I was running into problems when trying to scan an input
>file using c notation which is less efficient of memory, so I'm in the
>process of revising all of the I/O to use c++ resources.
This surprises me; I'd have thought stdio was more memory-efficient than
iostreams, if it's an issue at all (which I rather doubt). Regardless, a
segmentation fault is an indication of a memory access bug in your
program rather than running out of memory (it may not have happened in
Visual C simply because you were lucky in the way Visual C allocated
memory for you), so you may be trying to fix the wrong problem by doing
all this rewriting. (Of course, you may be lucky and accidentally fix it
in the process, or the problem may have been that you didn't know how to
use stdio and are more successful in using iostreams, but I suppose it
depends whether you actually want to know what you're doing ...)
>In general, I am beginning to notice that gcc's posture is that you do more
>for yourself. It also seems to be strictly limited to ANSI c. For example,
>there doesn't seem to be any support for min, max, and itoa and I ended up
>writing/rewriting that portion of the code
I think you desperately need to read 'info gcc' and 'info libc'. gcc is
notoriously far from limited to ANSI C. :)
Actually, your problem is not with gcc, it seems to be that the GNU C
Library (libc/glibc) doesn't have what you want; it's far from limited
to ANSI C either, but any C programmer worth his/her salt knows that if
you use extensions in your code you should expect them not to be
portable. glibc simply has different extensions to Visual C; in general
I've found it a much more helpful and much better documented C library
than the Microsoft one, but I may be biased.
Besides, min(), max(), and itoa() are hardly difficult. How about:
#define min(a,b) ((a) < (b) ? (a) : (b))
#define max(a,b) ((a) > (b) ? (a) : (b))
... or equivalent function definitions if the double evaluation bothers
you, and sprintf() instead of itoa()? If you program in ANSI C wherever
possible to start with rather than lazily using extensions, you'll have
a much easier time of it.
>Is there a separate users group for gcc?
gnu.gcc.help?
HTH,
--
Colin Watson [cjw44@cam.ac.uk]
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