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.
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.