"Richard L. Hamilton" <[EMAIL PROTECTED]> wrote:
> > My questions are:
> >
> > - How do I get the 32 bit ARG_MAX value from inside a
> > 64 bit program?
>
> Well, unless someone adds an _SC_ARG32_MAX and _SC_ARG64_MAX,
There is
#define _ARG_MAX32 1048320 /* max length of args to exec 32-bit program */
#define _ARG_MAX64 2096640 /* max length of args to exec 64-bit program */
> I suppose you need to popen() a helper program of the bitness other
> than your own that looks this up for you. You'd want to have a flag,
> so you only did that the first time you needed to know, and cached
> the value for subsequent use.
This does not seem to be a good solution
> > - What is the best way to detect whether "cmd" is a
> > 32 os a 64 bit binary?
>
> I'm not sure that's generally answerable. If the executable is also readable,
> you can do anything from run "file" on it to using the libelf functions (or
> the
> even more generic and portable GNU bfd library if available) to discover its
> type, with a library call of course being much more efficient than calling an
> external program. But an executable doesn't have to be readable, in which
> case I suppose you have to make the safer assumption, in this case that it's
> a 32-bit process.
Well, there is gelf_getclass()
> In general, I have a problem with people using insanely large argument lists;
Then you seem to missunderstand the background.
> a directory with hundreds of thousands of files probably won't perform well
> anyway, and aside from wildcard expansions, there's really no excuse _at_all_,
> for it IMO (and it's their responsibility to only use wildcards when their
> expansions
I am not sure if you ever did think about the problem.
- Your keyword "wildcard" does not apply at all
- Try to write a simple command that count the lines of code in ON
> could safely be expected to be reasonable sized). That's what xargs, or a
> program reading its stdin rather than taking args, is for. (And I remember
> the
xargs is the wrong solution for a problem - xargs does not deal with all
possible filenames, "find . -exec bla {} +" does.
> really old days when the max arg list size was something tiny, like 5120 or
> so.)
This is the limit from the 1970s. In the mid 1980s it was 20000 and since
SunOS-4.0 it is 1 MB, so the 1 MB limit is 20 years old now.
Jörg
--
EMail:[EMAIL PROTECTED] (home) Jörg Schilling D-13353 Berlin
[EMAIL PROTECTED] (uni)
[EMAIL PROTECTED] (work) Blog: http://schily.blogspot.com/
URL: http://cdrecord.berlios.de/private/ ftp://ftp.berlios.de/pub/schily
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