@acindex{PROG_GREP}
@ovindex GREP
On AIX the default @code{grep} silently truncates long lines on the
-input before matching. On Solaris 9 @code{/usr/bin/grep} does not
+input before matching. On Solaris, @code{/usr/bin/grep} does not
understand the @option{-e} option. On NeXT, @code{grep} understands only a
single @option{-e} option. This macro looks for @sc{gnu} Grep or
else the best available @code{grep} or @code{ggrep} in the user's
@c @fuindex vsprintf
@prindex @code{vsprintf}
The ISO C standard says @code{sprintf} and @code{vsprintf} return the
-number of bytes written, but on some old systems (SunOS 4 for
+number of bytes written, but on some ancient systems (SunOS 4 for
instance) they return the buffer pointer instead.
@item @code{sscanf}
Paul Eggert notes that: ISO C 1999 says that @file{inttypes.h} includes
@file{stdint.h}, so there's no need to include @file{stdint.h}
separately in a standard environment. Many implementations have
-@file{inttypes.h} but not @file{stdint.h} (e.g., Solaris 7), but I don't
+@file{inttypes.h} but not @file{stdint.h} (e.g., Solaris 7), but we don't
know of any implementation that has @file{stdint.h} but not
-@file{inttypes.h}. Nor do I know of any free software that includes
-@file{stdint.h}; @file{stdint.h} seems to be a creation of the committee.
+@file{inttypes.h}.
@item @file{linux/irda.h}
@hdrindex{linux/irda.h}
@item Don't rely on correct @code{#line} support
On Solaris 8, @command{c89} (Sun WorkShop 6 update 2 C 5.3 Patch
-111679-08 2002/05/09)) rejects @code{#line} directives whose line
-numbers are greater than 32767. In addition, nothing in @sc{posix}
-makes this invalid. That is the reason why Autoconf stopped issuing
+111679-08 2002/05/09)) diagnoses @code{#line} directives whose line
+numbers are greater than 32767. In addition, nothing in Posix
+makes this invalid. That is why Autoconf stopped issuing
@code{#line} directives.
@end table
Many older shells (including the Bourne shell) implement here-documents
inefficiently. And some shells mishandle large here-documents: for
-example, Solaris 8 @command{dtksh}, which is derived from
-Korn shell version M-12/28/93d, mishandles variable expansion that occurs
-on 1024-byte buffer boundaries within a here-document. Users can
-generally fix these problems by using a faster or more reliable
-shell, e.g., by using the command @samp{bash ./configure} rather than
+example, Solaris @command{dtksh}, which is derived from Korn shell
+version M-12/28/93d, mishandles variable expansion that occurs on
+1024-byte buffer boundaries within a here-document. Users can generally
+fix these problems by using a faster or more reliable shell, e.g., by
+using the command @samp{bash ./configure CONFIG_SHELL=bash} rather than
plain @samp{./configure}.
Some shells can be extremely inefficient when there are a lot of
@sp 1
-The Solaris @command{sh} has a frightening bug in its interpretation
+Solaris @command{/bin/sh} has a frightening bug in its interpretation
of this. Imagine you need set a variable to a string containing
-@samp{@}}. This @samp{@}} character confuses the Solaris @command{sh}
+@samp{@}}. This @samp{@}} character confuses Solaris @command{/bin/sh}
when the affected variable was already set. This bug can be exercised
by running:
@example
$ @kbd{showrev -c /bin/sh | grep version}
-Command version: SunOS 5.9 Generic May 2002
+Command version: SunOS 5.10 Generic January 2005
$ @kbd{echo $(echo blah)}
syntax error: `(' unexpected
@end example
When setting several variables in a row, be aware that the order of the
evaluation is undefined. For instance @samp{foo=1 foo=2; echo $foo}
-gives @samp{1} with sh on Solaris, but @samp{2} with Bash. You must use
+gives @samp{1} with Solaris @command{/bin/sh}, but @samp{2} with Bash.
+You must use
@samp{;} to enforce the order: @samp{foo=1; foo=2; echo $foo}.
Don't rely on the following to find @file{subdir/program}:
@prindex @command{!}
The Unix version 7 shell did not support
negating the exit status of commands with @command{!}, and this feature
-is still absent from more modern shells (e.g., Solaris 9 @command{sh}).
+is still absent from more modern shells (e.g., Solaris @command{/bin/sh}).
Shell code like this:
@example
$
@end example
-Even with this, SunOS 5.7 ksh matches a backslash if the set contains any
+Even with this, Solaris @command{ksh} matches a backslash if the set
+contains any
of the characters @samp{|}, @samp{&}, @samp{(}, or @samp{)}.
Conversely, Tru64 @command{ksh} (circa 2003) erroneously always matches
Many shells still do not support parenthesized cases, which is a pity
for those of us using tools that rely on balanced parentheses. For
-instance, Solaris 8's Bourne shell:
+instance, Solaris @command{/bin/sh}:
@example
$ @kbd{case foo in (foo) echo foo;; esac}
Do not use backslashes in the arguments, as there is no consensus on
their handling. On @samp{echo '\n' | wc -l}, the @command{sh} of
Digital Unix 4.0 and @acronym{MIPS RISC/OS} 4.52, answer 2, but the Solaris
-@command{sh}, Bash, and Zsh (in @command{sh} emulation mode) report 1.
+@command{/bin/sh}, Bash, and Zsh (in @command{sh} emulation mode) report 1.
Please note that the problem is truly @command{echo}: all the shells
understand @samp{'\n'} as the string composed of a backslash and an
@samp{n}.
nonzero status, the trap also exits with nonzero status so that the
invoker can tell that an error occurred.
-Unfortunately, in some shells, such as Solaris 8 @command{sh}, an exit
+Unfortunately, in some shells, such as Solaris @command{/bin/sh}, an exit
trap ignores the @code{exit} command's argument. In these shells, a trap
cannot determine whether it was invoked by plain @code{exit} or by
@code{exit 1}. Instead of calling @code{exit} directly, use the
received by the shell when it is launched should be imported as a shell
variable marked as exported.
-Alas, many shells, such as Solaris 2.5, @sc{irix} 6.3, @sc{irix} 5.2,
+Alas, many shells, such as Solaris @command{/bin/sh},
+@sc{irix} 6.3, @sc{irix} 5.2,
@acronym{AIX} 4.1.5, and Digital Unix 4.0, forget to
@command{export} the environment variables they receive. As a result,
two variables coexist: the environment variable and the shell
@item @command{false}
@c ------------------
@prindex @command{false}
-Don't expect @command{false} to exit with status 1: in the native Bourne
-shell of Solaris 8 it exits with status 255.
+Don't expect @command{false} to exit with status 1: in native
+Solaris it exits with status 255.
@item @command{for}
@item @command{read}
@c ------------------
@prindex @command{read}
-Not all shells support @option{-r} (Solaris 9 @command{sh} for example).
+Not all shells support @option{-r} (Solaris @command{/bin/sh} for example).
@item @command{pwd}
the host system. But occasionally you may find it necessary to check
whether some arbitrary file exists. To do so, use @samp{test -f} or
@samp{test -r}. Do not use @samp{test -x}, because 4.3@acronym{BSD} does not
-have it. Do not use @samp{test -e} either, because Solaris 2.5 does not
-have it. To test for symbolic links on systems that have them, use
+have it. Do not use @samp{test -e} either, because Solaris @command{/bin/sh}
+lacks it. To test for symbolic links on systems that have them, use
@samp{test -h} rather than @samp{test -L}; either form conforms to
Posix 1003.1-2001, but older shells like Solaris 8
-@code{sh} support only @option{-h}.
+@code{/bin/sh} support only @option{-h}.
@item @command{test} (strings)
@c ---------------------------
Contrary to a common belief, @samp{test -n @var{string}} and
@samp{test -z @var{string}} @strong{are} portable. Nevertheless many
-shells (such as Solaris 2.5, @acronym{AIX} 3.2, @sc{unicos} 10.0.0.6,
+shells (such as Solaris, @acronym{AIX} 3.2, @sc{unicos} 10.0.0.6,
Digital Unix 4, etc.)@: have bizarre precedence and may be confused if
@var{string} looks like an operator:
@command{exit} itself?''
Bash considers @command{exit} to be the last command, while Zsh and
-Solaris 8 @command{sh} consider that when the trap is run it is
+Solaris @command{/bin/sh} consider that when the trap is run it is
@emph{still} in the @command{exit}, hence it is the previous exit status
that the trap receives:
include some limitations you should be aware of.
@table @asis
-@item @command{awk}
+@item Awk
@c ----------------
-@prindex @command{awk}
-Don't leave white space before the opening parenthesis in a user function call;
-@acronym{GNU} awk will reject it:
+@prindex Awk
+Don't leave white space before the opening parenthesis in a user function call.
+Posix does not allow this and @acronym{GNU} Awk rejects it:
@example
$ @kbd{gawk 'function die () @{ print "Aaaaarg!" @}
foo
@end example
-Some AWK, such as HPUX 11.0's native one, have regex engines fragile to
-inner anchors:
+Some Awk implementations, such as HPUX 11.0's native one, mishandle anchors:
@example
$ @kbd{echo xfoo | $AWK '/foo|^bar/ @{ print @}'}
@noindent
Either do not depend on such patterns (i.e., use @samp{/^(.*foo|bar)/},
-or use a simple test to reject such AWK@.
+or use a simple test to reject such implementations.
-@acronym{AIX} version 5.2 limits on the maximal length of regular
-expressions and literal strings in the program to 399.
+@acronym{AIX} version 5.2 has an arbitrary limit of 399 on the the
+length of regular expressions and literal strings in an Awk program.
-Some @command{awk}, such as Solaris 9's native one, have a limit of 99
+Traditional Awk implementations derived from Unix version 7, such as
+Solaris @command{/bin/awk}, have many limitations and do not
+conform to Posix. Nowadays @code{AC_PROG_AWK} (@pxref{Particular
+Programs}) will find you an Awk that doesn't have these problems, but if
+for some reason you prefer not to use @code{AC_PROG_AWK} you may need to
+address them.
+
+Traditional Awk does not support multidimensional arrays or user-defined
+functions.
+
+Traditional Awk does not support the @option{-v} option. You can use
+assignments after the program instead, e.g., @command{$AWK '@{print v
+$1@}' v=x}; however, don't forget that such assignments are not
+evaluated until they are encountered (e.g., after any @code{BEGIN}
+action).
+
+Traditional Awk does not support the keywords @code{delete} or @code{do}.
+
+Traditional Awk does not support the expressions
+@code{@var{a}?@var{b}:@var{c}}, @code{!@var{a}}, @code{@var{a}^@var{b}},
+or @code{@var{a}^=@var{b}}.
+
+Traditional Awk does not support the predefined @code{CONVFMT} variable.
+
+Traditional Awk supports only the predefined functions @code{exp},
+@code{int}, @code{length}, @code{log}, @code{split}, @code{sprintf},
+@code{sqrt}, and @code{substr}.
+
+Traditional Awk @code{getline} is not at all compatible with Posix;
+avoid it.
+
+Traditional Awk @code{split} supports only two arguments.
+
+Traditional Awk has a limit of 99
fields in a record. You may be able to circumvent this problem by using
-the builtin function @code{split}.
+@code{split}.
@item @command{cat}
@c ----------------
@prindex @command{cat}
-Don't rely on any option. The option @option{-v}, which displays
-non-printing characters, @emph{seems} portable, though.
+Don't rely on any option.
@item @command{cc}
@prindex @command{cp}
Avoid the @option{-r} option, since its behavior is not specified by
Posix. Use @option{-R} instead. On @acronym{GNU} hosts the two options
-are equivalent, but on Solaris 9 hosts (for example) @command{cp -r}
+are equivalent, but on Solaris hosts (for example) @command{cp -r}
reads from pipes instead of replicating them.
Some @command{cp} implementations (e.g., BSD/OS 4.2) do not allow
/tmp/newdir/} if @file{/tmp/newdir} does not exist.
@c This is thanks to Ian.
-SunOS @command{cp} does not support @option{-f}, although its
+SunOS 4 @command{cp} does not support @option{-f}, although its
@command{mv} does. It's possible to deduce why @command{mv} and
@command{cp} are different with respect to @option{-f}. @command{mv}
prompts by default before overwriting a read-only file. @command{cp}
@command{cp} implementations use @code{utimes}, which has
1-microsecond resolution. These newer implementations include GNU
coreutils 5.0.91 or later, and Solaris 8 (sparc) patch 109933-02 or
-later. Unfortunately as of September 2003 there is still no system
+later. Unfortunately as of June 2005 there is still no system
call to set time stamps to the full nanosecond resolution.
Bob Proulx notes that @samp{cp -p} always @emph{tries} to copy
@c -----------------
@prindex @command{find}
The option @option{-maxdepth} seems to be @acronym{GNU} specific.
-Tru64 v5.1, Net@acronym{BSD} 1.5 and Solaris 2.5 @command{find}
+Tru64 v5.1, Net@acronym{BSD} 1.5 and Solaris @command{find}
commands do not understand it.
The replacement of @samp{@{@}} is guaranteed only if the argument is
@c -----------------
@prindex @command{grep}
Don't use @samp{grep -q} to suppress output, because many @command{grep}
-implementations (e.g., Solaris 10) do not support @option{-q}.
+implementations (e.g., Solaris) do not support @option{-q}.
Don't use @samp{grep -s} to suppress output either, because Posix
says @option{-s} does not suppress output, only some error messages;
also, the @option{-s} option of traditional @command{grep} behaved
Some traditional @command{grep} implementations do not work on long
input lines. Also, many implementations do not support multiple regexps
-with @option{-e}: they either reject @samp{-e} entirely (e.g., Solaris
-10) or honor only the last pattern (e.g., @acronym{IRIX} 6.5). To
+with @option{-e}: they either reject @samp{-e} entirely (e.g., Solaris)
+or honor only the last pattern (e.g., @acronym{IRIX} 6.5). To
work around these problems, invoke @code{AC_PROG_GREP} and then use
@code{$GREP}.
Posix does not clearly specify whether @samp{mkdir -p foo}
should succeed when @file{foo} is a symbolic link to an already-existing
-directory. GNU Coreutils 5.1.0 @command{mkdir} succeeds, but Solaris 9
+directory. GNU Coreutils 5.1.0 @command{mkdir} succeeds, but Solaris
@command{mkdir} fails.
Not all @code{mkdir -p} implementations are thread-safe. When it is not
and you call @code{mkdir -p a/b} and @code{mkdir -p a/c} at the same
time, both will detect that @file{a/} is missing, one will create
@file{a/}, then the other will try to create @file{a/} and die with a
-@code{File exists} error. At least Solaris 8, NetBSD 1.6, and OpenBSD
+@code{File exists} error. At least Solaris 10, NetBSD 1.6, and OpenBSD
3.4 have an unsafe @code{mkdir -p}. GNU Coreutils (since Fileutils
version 4.0c), FreeBSD 5.0, and NetBSD-current are known to have a
race-free @code{mkdir -p}. This possible race is harmful in parallel
an input buffer limited to 4000 bytes.
Alternation, @samp{\|}, is common but Posix does not require its
-support, so it should be avoided in portable scripts. Solaris 8
+support, so it should be avoided in portable scripts. Solaris
@command{sed} does not support alternation; e.g., @samp{sed '/a\|b/d'}
deletes only lines that contain the literal string @samp{a|b}.
quite portable to modern hosts, but is not supported by some older
@command{sed} implementations like SVR3.
-Some @command{sed} implementations, e.g., Solaris 10,
+Some @command{sed} implementations, e.g., Solaris,
restrict the special role of the asterisk to one-character regular expressions.
This may lead to unexpected behavior:
Posix requires that you must not have any white space between
@samp{!} and the following command. It is OK to have blanks between
-the address and the @samp{!}. For instance, on Solaris 8:
+the address and the @samp{!}. For instance, on Solaris:
@example
$ @kbd{echo "foo" | sed -n '/bar/ ! p'}
@item @code{$<}
Posix says that the @samp{$<} construct in makefiles can be
used only in inference rules and in the @samp{.DEFAULT} rule; its
-meaning in ordinary rules is unspecified. Solaris 8's @command{make}
+meaning in ordinary rules is unspecified. Solaris @command{make}
for instance will replace it with the empty string. OpenBSD (3.0 and
later) @command{make} will diagnose these uses and error out.
@cindex @code{VPATH} and automatic rule rewriting
@cindex automatic rule rewriting and @code{VPATH}
-Some @command{make} implementations, such as SunOS @command{make} or
+Some @command{make} implementations, such as SunOS 4 @command{make} or
OSF1/Tru64 @command{make}, will search prerequisites in @code{VPATH} and
rewrite all their occurrences in the rule appropriately.
@noindent
However the "prerequisite rewriting" still applies here. So if
-@file{if.c} is in @file{../pkg/src}, SunOS @command{make} and OSF1/Tru64
+@file{if.c} is in @file{../pkg/src}, SunOS 4 @command{make} and OSF1/Tru64
@command{make} will execute
@smallexample
done
@end example
-The above @code{install-HEADERS} rule is not SunOS-proof because @code{for
+The above @code{install-HEADERS} rule is not SunOS-4-proof because @code{for
i in $(HEADERS);} will be expanded as @code{for i in f.h g.h h.h;}
where @code{f.h} and @code{g.h} are plain words and are hence
subject to @code{VPATH} adjustments.
directory does not even exist, this just means that the simplification
occurred before the file was checked for.)
-For the record here is how SunOS @command{make} behaves on this
+For the record here is how SunOS 4 @command{make} behaves on this
very same example.
@smallexample
% make
projects / thirdparty / autoconf.git / commitdiff
