Re: Request for portability test of strerror().

Pete, can you handle coversion of fprintf(stderr) to elog at the same
time?  It would be nice, but it can only be done in places where elog is
safe.


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> I'm preparing a patch for backend/utils/error to make the printing of
> error messages more robust.  It would be very helpful if people on
> different systems would compile and run the following test program to
> check the behaviour of strerror().
>
> The PostgreSQL code is called only in exceptional circumstances, so
> regular testing of my changes is not possible.
>
> According to the standards UNIX95 (aka XPG4v2) and later, strerror()
> should set errno to EINVAL if its argument is out of range.  Most
> compliant systems seem to return a default string with a number
> printed in it and so never set errno.
>
> sys_nerr was last in XPG2 but has now been dropped.  I'm hoping to
> remove it from the PostgreSQL code.
>
Content-Description: Test behaviour of strerror()

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>
> My results so far follow.  I've listed them by OS though there is also
> a dependency on libc.
>
> AIX 4.3:     errno = 0 after strerror(-1) returned "Error -1 occurred."
> Cygwin B20:  errno = 0 after strerror(-1) returned "error -1"
> IRIX 6.5:    errno = 0 after strerror(-1) returned NULL
> Redhat 6.2:  errno = 0 after strerror(-1) returned "Unknown error 4294967295"
> Solaris 2.6: errno = 0 after strerror(-1) returned NULL
> Solaris 7:   errno = 0 after strerror(-1) returned NULL
>
>
> What I'd like to know is whether any version of strerror() returns a
> non-NULL pointer that does not contain a print of the number.
> --
> Pete Forman                 -./\.- Disclaimer: This post is originated
> Western Geophysical           -./\.-  by myself and does not represent
> pete.forman@westgeo.com         -./\.-  the opinion of Baker Hughes or
> http://www.crosswinds.net/~petef  -./\.-  its divisions.


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