mirror of
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* doc/autoconf.texi: Use @acronym more consistently for acronyms
like BSD, GPL, LGPL. Fix minor English typos. (AC_STDC_HEADERS, AC_PROG_GCC_TRADITIONAL): Mention that these macros are becoming obsolete. (AC_STDC_HEADERS, AC_PROG_CC, AC_C_CONST, AC_C_VOLATILE): Use more modern terminology for which standard is what. (AC_PROG_CC): Mention gcc first, and remove obsolete references to egcs and to ansi2knr. (AC_PROG_CXX): Likewise. (AC_C_PROTOTYPES, Test Functions, AC_LIBOBJ vs LIBOBJS): Remove obsolete discussion about how to port to K&R. (Guidelines for Test Programs): Suggest AC_HEADER_STDBOOL rather than the obsolescent AC_HEADER_STDC. (AC_FOO_IFELSE vs AC_TRY_FOO): Don't use #error; test programs can't rely on it.
This commit is contained in:
Paul Eggert
parent
f1fb11eb87
commit
60a9e484c6
18
ChangeLog
18
ChangeLog
@ -1,3 +1,21 @@
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2006-03-10 Paul Eggert <eggert@cs.ucla.edu>
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* doc/autoconf.texi: Use @acronym more consistently for acronyms
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like BSD, GPL, LGPL. Fix minor English typos.
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(AC_STDC_HEADERS, AC_PROG_GCC_TRADITIONAL):
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Mention that these macros are becoming obsolete.
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(AC_STDC_HEADERS, AC_PROG_CC, AC_C_CONST, AC_C_VOLATILE):
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Use more modern terminology for which standard is what.
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(AC_PROG_CC): Mention gcc first, and remove obsolete references to egcs
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and to ansi2knr.
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(AC_PROG_CXX): Likewise.
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(AC_C_PROTOTYPES, Test Functions, AC_LIBOBJ vs LIBOBJS):
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Remove obsolete discussion about how to port to K&R.
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(Guidelines for Test Programs): Suggest AC_HEADER_STDBOOL rather than
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the obsolescent AC_HEADER_STDC.
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(AC_FOO_IFELSE vs AC_TRY_FOO): Don't use #error; test programs
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can't rely on it.
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2006-03-08 Ralf Wildenhues <Ralf.Wildenhues@gmx.de>
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* tests/c.at (AC_PROG_CPP without warnings, AC_PROG_CPP via CC):
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@ -3867,8 +3867,8 @@ Posix prefers @code{setenv} to @code{putenv}; among other things,
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Posix specifies that @code{putenv} puts the given string directly in
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@code{environ}, but some systems make a copy of it instead (e.g.,
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glibc 2.0, or BSD). And when a copy is made, @code{unsetenv} might
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not free it, causing a memory leak (e.g., FreeBSD 4).
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glibc 2.0, or @acronym{BSD}). And when a copy is made, @code{unsetenv} might
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not free it, causing a memory leak (e.g., Free@acronym{BSD} 4).
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On some systems @code{putenv ("FOO")} removes @samp{FOO} from the
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environment, but this is not standard usage and it dumps core
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@ -3889,10 +3889,10 @@ NextStep).
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@prindex @code{signal}
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Normally @code{signal} takes a handler function with a return type of
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@code{void}, but some old systems required @code{int} instead. Any
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actual @code{int} value returned is not used, this is only a
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actual @code{int} value returned is not used; this is only a
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difference in the function prototype demanded.
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All systems we know of in current use take @code{void}. Presumably
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All systems we know of in current use return @code{void}. The
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@code{int} was to support K&R C, where of course @code{void} is not
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available. @code{AC_TYPE_SIGNAL} (@pxref{Particular Types}) can be
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used to establish the correct type in all cases.
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@ -4275,7 +4275,7 @@ Check for @code{getmntent} in the standard C library, and then in the
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@prindex @code{getpgid}
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@prindex @code{getpgrp}
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Define @code{GETPGRP_VOID} if it is an error to pass 0 to
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@code{getpgrp}; this is the Posix behavior. On older BSD
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@code{getpgrp}; this is the Posix behavior. On older @acronym{BSD}
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systems, you must pass 0 to @code{getpgrp}, as it takes an argument and
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behaves like Posix's @code{getpgid}.
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@ -4613,7 +4613,7 @@ Suitable replacements for many such problem functions are available from
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@uref{http://www.gnu.org/software/gnulib/, Gnulib}, which aims to
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provide a centralized repository of such portability functions (among
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other things). The source files are available online, under various
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licences, mostly GNU GPL or GNU LGPL.
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licences, mostly @acronym{GNU} @acronym{GPL} or @acronym{GNU} @acronym{LGPL}.
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@defmac AC_LIBOBJ (@var{function})
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@acindex{LIBOBJ}
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@ -4799,7 +4799,7 @@ On many systems (e.g., Darwin), @file{stdio.h} is a prerequisite.
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@item @file{sys/mount.h}
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@hdrindex{sys/mount.h}
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On FreeBSD 4.8 on ia32 and using gcc version 2.95.4,
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On Free@acronym{BSD} 4.8 on ia32 and using gcc version 2.95.4,
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@file{sys/params.h} is a prerequisite.
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@item @file{sys/ptem.h}
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@ -5004,34 +5004,41 @@ fi
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@hdrindex{string.h}
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@hdrindex{float.h}
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@hdrindex{ctype.h}
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Define @code{STDC_HEADERS} if the system has @acronym{ANSI} C header files.
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Define @code{STDC_HEADERS} if the system has C header files
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conforming to @acronym{ANSI} C89 (@acronym{ISO} C90).
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Specifically, this macro checks for @file{stdlib.h}, @file{stdarg.h},
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@file{string.h}, and @file{float.h}; if the system has those, it
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probably has the rest of the @acronym{ANSI} C header files. This macro also
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probably has the rest of the C89 header files. This macro also
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checks whether @file{string.h} declares @code{memchr} (and thus
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presumably the other @code{mem} functions), whether @file{stdlib.h}
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declare @code{free} (and thus presumably @code{malloc} and other related
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functions), and whether the @file{ctype.h} macros work on characters
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with the high bit set, as @acronym{ANSI} C requires.
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with the high bit set, as the C standard requires.
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Use @code{STDC_HEADERS} instead of @code{__STDC__} to determine whether
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the system has @acronym{ANSI}-compliant header files (and probably C library
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functions) because many systems that have GCC do not have @acronym{ANSI} C
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header files.
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Nowadays this macro is becoming obsolete. However, if you use it, your
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code can refer to @code{STDC_HEADERS} instead of @code{__STDC__} to
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determine whether the system has conforming header files (and probably C
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library functions). This is useful if you worry about portability
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to ancient systems that lack C89 header files.
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@hdrindex{string.h}
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@hdrindex{strings.h}
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On systems without @acronym{ANSI} C headers, there is so much variation
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Nowadays @file{string.h} is part of the C standard and declares functions like
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@code{strcpy}, and @file{strings.h} is standardized by Posix and declares
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@acronym{BSD} functions like @code{bcopy}; but
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historically, string functions were a major sticking point in this area.
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If you worry about portability to ancient systems without standard
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headers, there is so much variation
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that it is probably easier to declare the functions you use than to
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figure out exactly what the system header files declare. Some systems
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contain a mix of functions from @acronym{ANSI} and @acronym{BSD}; some are
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mostly @acronym{ANSI} but lack @samp{memmove}; some define the
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figure out exactly what the system header files declare. Some ancient systems
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contain a mix of functions from the C standard and from @acronym{BSD}; some are
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mostly standard but lack @samp{memmove}; some define the
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@acronym{BSD} functions as macros in @file{string.h} or
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@file{strings.h}; some have only the @acronym{BSD} functions but
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@file{string.h}; some declare the memory functions in @file{memory.h},
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some in @file{string.h}; etc. It is probably sufficient to check for
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one string function and one memory function; if the library has the
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@acronym{ANSI} versions of those then it probably has most of the others.
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standard versions of those then it probably has most of the others.
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If you put the following in @file{configure.ac}:
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@example
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@ -5755,21 +5762,19 @@ like the default order, then you could invoke @code{AC_PROG_CC} like
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this:
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@example
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AC_PROG_CC([cl egcs gcc cc])
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AC_PROG_CC([gcc cl cc])
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@end example
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If the C compiler is not in @acronym{ANSI} mode by default, try to add an
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option to output variable @code{CC} to make it so. This macro tries
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various options that select @acronym{ANSI} C on some system or another. It
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considers the compiler to be in @acronym{ANSI} mode if it handles function
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prototypes correctly.
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If the C compiler does not handle function prototypes correctly by
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default, try to add an option to output variable @code{CC} to make it
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so. This macro tries various options that select standard-conformance
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modes on various systems.
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After calling this macro you can check whether the C compiler has been
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set to accept @acronym{ANSI} C; if not, the shell variable
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@code{ac_cv_prog_cc_c89} is set to @samp{no}. If you wrote your source
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code in @acronym{ANSI} C, you can make an un-@acronym{ANSI}fied copy of it by
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using the program @code{ansi2knr}, which comes with Automake. See also
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under @code{AC_C_PROTOTYPES} below.
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set to accept @acronym{ANSI} C89 (@acronym{ISO} C90); if not, the shell
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variable
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@code{ac_cv_prog_cc_c89} is set to @samp{no}. See also
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@code{AC_C_PROTOTYPES} below.
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If using the @acronym{GNU} C compiler, set shell variable @code{GCC} to
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@samp{yes}. If output variable @code{CFLAGS} was not already set, set
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@ -5893,8 +5898,8 @@ to bypass this test.
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@defmac AC_C_CONST
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@acindex{C_CONST}
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@cvindex const
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If the C compiler does not fully support the @acronym{ANSI} C qualifier
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@code{const}, define @code{const} to be empty. Some C compilers that do
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If the C compiler does not fully support the @code{const} keyword,
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define @code{const} to be empty. Some C compilers that do
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not define @code{__STDC__} do support @code{const}; some compilers that
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define @code{__STDC__} do not completely support @code{const}. Programs
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can simply use @code{const} as if every C compiler supported it; for
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@ -5952,7 +5957,7 @@ your code. However, given that the compiler does not support
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@code{volatile}, you are at its mercy anyway. At least your
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program will compile, when it wouldn't before.
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In general, the @code{volatile} keyword is a feature of @acronym{ANSI} C, so
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In general, the @code{volatile} keyword is a standard C feature, so
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you might expect that @code{volatile} is available only when
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@code{__STDC__} is defined. However, Ultrix 4.3's native compiler does
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support volatile, but does not define @code{__STDC__}.
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@ -6010,31 +6015,9 @@ to that spelling.
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@cvindex PARAMS
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If function prototypes are understood by the compiler (as determined by
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@code{AC_PROG_CC}), define @code{PROTOTYPES} and @code{__PROTOTYPES}.
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In the case the compiler does not handle
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prototypes, you should use @code{ansi2knr}, which comes with the
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Automake distribution, to unprotoize function definitions. For
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function prototypes, you should first define @code{PARAMS}:
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@example
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#ifndef PARAMS
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# if PROTOTYPES
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# define PARAMS(protos) protos
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# else /* no PROTOTYPES */
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# define PARAMS(protos) ()
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# endif /* no PROTOTYPES */
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#endif
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@end example
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@noindent
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then use it this way:
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@example
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size_t my_strlen PARAMS ((const char *));
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@end example
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@end defmac
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This macro also defines @code{__PROTOTYPES}; this is for the benefit of
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Defining @code{__PROTOTYPES} is for the benefit of
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header files that cannot use macros that infringe on user name space.
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@end defmac
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@defmac AC_PROG_GCC_TRADITIONAL
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@acindex{PROG_GCC_TRADITIONAL}
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@ -6044,7 +6027,7 @@ Add @option{-traditional} to output variable @code{CC} if using the
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@option{-traditional}. That usually happens when the fixed header files
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have not been installed on an old system. Since recent versions of the
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@acronym{GNU} C compiler fix the header files automatically when installed,
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this is becoming a less prevalent problem.
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this macro is becoming obsolete.
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@end defmac
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@ -6073,7 +6056,7 @@ didn't like the default order, then you could invoke @code{AC_PROG_CXX}
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like this:
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@example
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AC_PROG_CXX([cl KCC CC cxx cc++ xlC aCC c++ g++ egcs gcc])
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AC_PROG_CXX([gcc cl KCC CC cxx cc++ xlC aCC c++ g++])
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@end example
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If using the @acronym{GNU} C++ compiler, set shell variable @code{GXX} to
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@ -6172,7 +6155,7 @@ which, if specified, must be a blank-separated list of Fortran
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compilers to search for, just as in @code{AC_PROG_F77}.
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If the output variable @code{FCFLAGS} was not already set in the
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environment, then set it to @option{-g -02} for GNU @code{g77} (or
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environment, then set it to @option{-g -02} for @acronym{GNU} @code{g77} (or
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@option{-O2} where @code{g77} does not accept @option{-g}). Otherwise,
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set @code{FCFLAGS} to @option{-g} for all other Fortran compilers.
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@end defmac
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@ -6564,7 +6547,8 @@ available or the environments they provide.
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@defmac AC_AIX
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@acindex{AIX}
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@cvindex _ALL_SOURCE
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If on @acronym{AIX}, define @code{_ALL_SOURCE}. Allows the use of some @acronym{BSD}
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If on @acronym{AIX}, define @code{_ALL_SOURCE}.
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Allows the use of some @acronym{BSD}
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functions. Should be called before any macros that run the C compiler.
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@end defmac
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@ -6777,14 +6761,14 @@ to @code{return} in @code{main} is ignored.
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Test programs can use @code{#if} or @code{#ifdef} to check the values of
|
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preprocessor macros defined by tests that have already run. For
|
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example, if you call @code{AC_HEADER_STDC}, then later on in
|
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@file{configure.ac} you can have a test program that includes an
|
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@acronym{ANSI} C header file conditionally:
|
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example, if you call @code{AC_HEADER_STDBOOL}, then later on in
|
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@file{configure.ac} you can have a test program that includes
|
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@file{stdbool.h} conditionally:
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@example
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@group
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#if STDC_HEADERS
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# include <stdlib.h>
|
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#if HAVE_STDBOOL_H
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# include <stdbool.h>
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#endif
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@end group
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@end example
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@ -6797,17 +6781,8 @@ after running test programs and if the script is interrupted.
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@node Test Functions
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@subsection Test Functions
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Function declarations in test programs should have a prototype
|
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conditionalized for C++. In practice, though, test programs rarely need
|
||||
functions that take arguments.
|
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|
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@example
|
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#ifdef __cplusplus
|
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foo (int i)
|
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#else
|
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foo (i) int i;
|
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#endif
|
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@end example
|
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These days it's safe to assume support for function prototypes
|
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(introduced in C89).
|
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|
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Functions that test programs declare should also be conditionalized for
|
||||
C++, which requires @samp{extern "C"} prototypes. Make sure to not
|
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@ -6815,10 +6790,9 @@ include any header files containing clashing prototypes.
|
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|
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@example
|
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#ifdef __cplusplus
|
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extern "C" void *malloc (size_t);
|
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#else
|
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void *malloc ();
|
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extern "C"
|
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#endif
|
||||
void *valloc (size_t);
|
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@end example
|
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|
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If a test program calls a function with invalid parameters (just to see
|
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@ -10026,7 +10000,7 @@ the standard shell conform to Posix.
|
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A public-domain clone of the Korn shell called @command{pdksh} is widely
|
||||
available: it has most of the @samp{ksh88} features along with a few of
|
||||
its own. It will usually set @code{KSH_VERSION}, except if invoked as
|
||||
@command{/bin/sh} on OpenBSD, and similarly to Bash you can require
|
||||
@command{/bin/sh} on Open@acronym{BSD}, and similarly to Bash you can require
|
||||
Posix compatibility by running @samp{set -o posix}. Unfortunately, with
|
||||
@command{pdksh} 5.2.14 (the latest stable version as of February 2006)
|
||||
Posix mode is buggy and causes @command{pdksh} to depart from Posix in
|
||||
@ -10501,7 +10475,8 @@ esac
|
||||
@item $@{10@}
|
||||
@cindex positional parameters
|
||||
The 10th, 11th, @dots{} positional parameters can be accessed only after
|
||||
a @code{shift}. The 7th edition shell reported an error if given @code{$@{10@}};
|
||||
a @code{shift}. The 7th Edition shell reported an error if given
|
||||
@code{$@{10@}}, and
|
||||
Solaris 10 @command{/bin/sh} still acts that way:
|
||||
|
||||
@example
|
||||
@ -11302,7 +11277,7 @@ EOF
|
||||
@item @command{eval}
|
||||
@c -----------------
|
||||
@prindex @command{eval}
|
||||
In some shell implementations (e.g., older @command{ash}, OpenBSD 3.8
|
||||
In some shell implementations (e.g., older @command{ash}, Open@acronym{BSD} 3.8
|
||||
@command{sh}, @command{pdksh} v5.2.14 99/07/13.2, and @command{zsh}
|
||||
4.2.5), the arguments of @samp{eval} are evaluated in a context where
|
||||
@samp{$?} is 0, so they exhibit behavior like this:
|
||||
@ -11472,7 +11447,7 @@ fi
|
||||
A format string starting with a @samp{-} can cause problems.
|
||||
Bash (e.g., 2.05b) will interpret it as an options string and
|
||||
give an error. And @samp{--} to mark the end of options is not good
|
||||
in the NetBSD Almquist shell (e.g., 0.4.6) which will take that
|
||||
in the Net@acronym{BSD} Almquist shell (e.g., 0.4.6) which will take that
|
||||
literally as the format string. Putting the @samp{-} in a @samp{%c}
|
||||
or @samp{%s} is probably the easiest way to avoid doubt,
|
||||
|
||||
@ -11947,7 +11922,7 @@ Posix. Use @option{-R} instead. On @acronym{GNU} hosts the two options
|
||||
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
|
||||
Some @command{cp} implementations (e.g., @acronym{BSD/OS} 4.2) do not allow
|
||||
trailing slashes at the end of nonexistent destination directories. To
|
||||
avoid this problem, omit the trailing slashes. For example, use
|
||||
@samp{cp -R source /tmp/newdir} rather than @samp{cp -R source
|
||||
@ -11978,8 +11953,8 @@ source. The exact amount of truncation depends on the resolution of
|
||||
the system calls that @command{cp} uses; traditionally this was
|
||||
@code{utime}, which has 1-second resolution, but some newer
|
||||
@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
|
||||
1-microsecond resolution. These newer implementations include @acronym{GNU}
|
||||
Core Utilities 5.0.91 or later, and Solaris 8 (sparc) patch 109933-02 or
|
||||
later. Unfortunately as of January 2006 there is still no system
|
||||
call to set time stamps to the full nanosecond resolution.
|
||||
|
||||
@ -11990,17 +11965,19 @@ kernel allows it then it happens. If the kernel does not allow it then
|
||||
it does not happen. It is not something @command{cp} itself has control
|
||||
over.
|
||||
|
||||
In SysV any user can chown files to any other user, and SysV also had a
|
||||
non-sticky @file{/tmp}. That undoubtedly derives from the heritage of
|
||||
SysV in a business environment without hostile users. BSD changed this
|
||||
In Unix System V any user can chown files to any other user, and System
|
||||
V also has a non-sticky @file{/tmp}. That probably derives from the
|
||||
heritage of System V in a business environment without hostile users.
|
||||
@acronym{BSD} changed this
|
||||
to be a more secure model where only root can @command{chown} files and
|
||||
a sticky @file{/tmp} is used. That undoubtedly derives from the heritage
|
||||
of BSD in a campus environment.
|
||||
of @acronym{BSD} in a campus environment.
|
||||
|
||||
Linux by default follows BSD, but it can be configured to allow
|
||||
@command{chown}. HP-UX as an alternate example follows SysV, but it can
|
||||
@acronym{GNU}/Linux and Solaris by default follow @acronym{BSD}, but
|
||||
can be configured to allow a System V style @command{chown}. On the
|
||||
other hand, @acronym{HP-UX} follows System V, but can
|
||||
be configured to use the modern security model and disallow
|
||||
@command{chown}. Since it is an administrator configurable parameter
|
||||
@command{chown}. Since it is an administrator-configurable parameter
|
||||
you can't use the name of the kernel as an indicator of the behavior.
|
||||
|
||||
|
||||
@ -12370,16 +12347,18 @@ None of @command{mkdir}'s options are portable to older systems. Instead of
|
||||
|
||||
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
|
||||
@command{mkdir} fails.
|
||||
directory. The @acronym{GNU} Core Utilities 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 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
|
||||
@code{File exists} error. At least Solaris 10, Net@acronym{BSD} 1.6, and Open@acronym{BSD}
|
||||
3.4 have an unsafe @code{mkdir -p}. The @acronym{GNU} Core Utilities
|
||||
(since @samp{fileutils}
|
||||
version 4.0c), Free@acronym{BSD} 5.0, and Net@acronym{BSD}-current are
|
||||
known to have a
|
||||
race-free @code{mkdir -p}. This possible race is harmful in parallel
|
||||
builds when several @file{Makefile} rules call @code{mkdir -p} to
|
||||
construct directories. You may use @command{mkinstalldirs} or
|
||||
@ -12700,13 +12679,13 @@ are executed by the shell, all its weaknesses are inherited@enddots{}
|
||||
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 @command{make}
|
||||
for instance will replace it with the empty string. OpenBSD (3.0 and
|
||||
for instance will replace it with the empty string. Open@acronym{BSD} (3.0 and
|
||||
later) @command{make} will diagnose these uses and error out.
|
||||
|
||||
@item Command execution
|
||||
Since 1992 Posix has required that @command{make} must invoke
|
||||
each command with the equivalent of a @samp{sh -c} subshell. However,
|
||||
many @command{make} implementations, including BSD make through 2004,
|
||||
many @command{make} implementations, including @acronym{BSD} make through 2004,
|
||||
use @samp{sh -e -c} instead, and the @option{-e} option causes the
|
||||
subshell to exit immediately if a subsidiary simple-command fails. For
|
||||
example, the command @samp{touch T; rm -f U} will always attempt to
|
||||
@ -12848,7 +12827,7 @@ sub-@code{make}s as expected.
|
||||
|
||||
This syntax (@code{foo=bar make -e}) is portable only when used
|
||||
outside of a @file{Makefile}, for instance from a script or from the
|
||||
command line. When run inside a @command{make} rule, GNU
|
||||
command line. When run inside a @command{make} rule, @acronym{GNU}
|
||||
@command{make} 3.80 and prior versions forget to propagate the
|
||||
@code{-e} option to sub-@command{make}s.
|
||||
|
||||
@ -12892,7 +12871,7 @@ SHELL = @@SHELL@@
|
||||
|
||||
Do not force @code{SHELL = /bin/sh} because that is not correct
|
||||
everywhere. For instance @acronym{DJGPP} lacks @code{/bin/sh}, and when
|
||||
its GNU @code{make} port sees such a setting it enters a special
|
||||
its @acronym{GNU} @code{make} port sees such a setting it enters a special
|
||||
emulation mode where features like pipes and redirections are emulated
|
||||
on top of DOS's @command{command.com}. Unfortunately this emulation is
|
||||
incomplete; for instance it does not handle command substitutions.
|
||||
@ -12940,12 +12919,12 @@ all:
|
||||
|
||||
@item The @file{obj/} subdirectory.
|
||||
@cindex @file{obj/}, subdirectory
|
||||
@cindex BSD @command{make} and @file{obj/}
|
||||
@cindex @acronym{BSD} @command{make} and @file{obj/}
|
||||
|
||||
Never name one of your subdirectories @file{obj/} if you don't like
|
||||
surprises.
|
||||
|
||||
If an @file{obj/} directory exists, BSD @command{make} will enter it
|
||||
If an @file{obj/} directory exists, @acronym{BSD} @command{make} will enter it
|
||||
before reading @file{Makefile}. Hence the @file{Makefile} in the
|
||||
current directory will not be read.
|
||||
|
||||
@ -13263,13 +13242,14 @@ builds the file locally using the file name given in the @file{Makefile}.
|
||||
If a target does not need to be rebuilt, @acronym{GNU} @command{make} uses the
|
||||
file name found during the @code{VPATH} search.
|
||||
|
||||
Other @command{make} implementations, like NetBSD @command{make}, are
|
||||
Other @command{make} implementations, like Net@acronym{BSD} @command{make}, are
|
||||
easier to describe: the file name found during the @code{VPATH} search
|
||||
will be used whether the target needs to be rebuilt or not. Therefore
|
||||
new files are created locally, but existing files are updated at their
|
||||
@code{VPATH} location.
|
||||
|
||||
OpenBSD and FreeBSD @command{make}s, however, will never perform a
|
||||
Open@acronym{BSD} and Free@acronym{BSD} @command{make}s, however, will
|
||||
never perform a
|
||||
@code{VPATH} search for a dependency which has an explicit rule.
|
||||
This is extremely annoying.
|
||||
|
||||
@ -13277,7 +13257,7 @@ When attempting a @code{VPATH} build for an autoconfiscated package
|
||||
(e.g., @code{mkdir build && cd build && ../configure}), this means the
|
||||
@acronym{GNU}
|
||||
@command{make} will build everything locally in the @file{build}
|
||||
directory, while BSD @command{make} will build new files locally and
|
||||
directory, while @acronym{BSD} @command{make} will build new files locally and
|
||||
update existing files in the source directory.
|
||||
|
||||
@example
|
||||
@ -13313,8 +13293,9 @@ Building foo.x
|
||||
Building bar.x
|
||||
@end example
|
||||
|
||||
Note how NetBSD @command{make} updates @file{../bar.x} in its VPATH
|
||||
location, and how FreeBSD, OpenBSD, and Tru64 @command{make} always
|
||||
Note how Net@acronym{BSD} @command{make} updates @file{../bar.x} in its
|
||||
VPATH location, and how Free@acronym{BSD}, Open@acronym{BSD}, and Tru64
|
||||
@command{make} always
|
||||
update @file{bar.x}, even when @file{../bar.x} is up to date.
|
||||
|
||||
Another point worth mentioning is that once @acronym{GNU} @command{make} has
|
||||
@ -13362,7 +13343,8 @@ Note that if you drop away the command from the @code{bar.x: newer.x}
|
||||
rule, @acronym{GNU} @command{make} will magically start to work: it
|
||||
knows that @code{bar.x} hasn't been updated, therefore it doesn't
|
||||
discard the result from @code{VPATH} (@file{../bar.x}) in succeeding
|
||||
uses. Tru64 will also work, but FreeBSD and OpenBSD still don't.
|
||||
uses. Tru64 will also work, but Free@acronym{BSD} and Open@acronym{BSD}
|
||||
still don't.
|
||||
|
||||
@example
|
||||
% @kbd{cat Makefile}
|
||||
@ -16007,48 +15989,6 @@ AC_LIBOBJ([malloc])
|
||||
|
||||
@sp 1
|
||||
|
||||
@ovindex U
|
||||
@cindex @code{$U}
|
||||
When asked for automatic de-ANSI-fication, Automake needs
|
||||
@code{LIBOBJS}'ed file names to have @samp{$U} appended to the base
|
||||
names. Libtool requires the definition of @code{LTLIBOBJS}, whose
|
||||
suffixes are mapped to @samp{.lo}. People used to run snippets such as:
|
||||
|
||||
@example
|
||||
# This is necessary so that .o files in LIBOBJS are also built via
|
||||
# the ANSI2KNR-filtering rules.
|
||||
LIBOBJS=`echo "$LIBOBJS" | sed 's/\.o /\$U.o /g;s/\.o$/\$U.o/'`
|
||||
LTLIBOBJS=`echo "$LIBOBJS" | sed 's/\.o/\.lo/g'`
|
||||
AC_SUBST([LTLIBOBJS])
|
||||
@end example
|
||||
|
||||
@noindent
|
||||
Note that this code is @emph{wrong}, because @samp{.o} is not the only
|
||||
possible extension@footnote{
|
||||
@c
|
||||
Yet another reason why assigning @code{LIBOBJS} directly is discouraged.
|
||||
@c
|
||||
}! It should have read:
|
||||
|
||||
@example
|
||||
# This is necessary so that .o files in LIBOBJS are also built via
|
||||
# the ANSI2KNR-filtering rules.
|
||||
LIB@@&t@@OBJS=`echo "$LIB@@&t@@OBJS" |
|
||||
sed 's,\.[[^.]]* ,$U&,g;s,\.[[^.]]*$,$U&,'`
|
||||
LTLIBOBJS=`echo "$LIB@@&t@@OBJS" |
|
||||
sed 's,\.[[^.]]* ,.lo ,g;s,\.[[^.]]*$,.lo,'`
|
||||
AC_SUBST([LTLIBOBJS])
|
||||
@end example
|
||||
|
||||
@sp 1
|
||||
|
||||
You no longer have to use this: @code{AC_OUTPUT} normalizes
|
||||
@code{LIBOBJS} and @code{LTLIBOBJS} (hence it works with any version of
|
||||
Automake and Libtool). Just remove these lines (@command{autoupdate}
|
||||
cannot handle this task, since this is not a macro).
|
||||
|
||||
Note that @code{U} must not be used in your Makefiles.
|
||||
|
||||
@ovindex LIBOBJDIR
|
||||
When used with Automake 1.10 or newer, a suitable value for
|
||||
@code{LIBOBJDIR} is set so that the @code{LIBOBJS} and @code{LTLIBOBJS}
|
||||
@ -16113,7 +16053,7 @@ The above example, properly written would (i) use
|
||||
@group
|
||||
AC_COMPILE_IFELSE([AC_LANG_PROGRAM(
|
||||
[[#if !defined _AIX
|
||||
# error _AIX not defined
|
||||
error: This isn't AIX!
|
||||
#endif
|
||||
]])],
|
||||
[is_aix=yes],
|
||||
@ -16705,12 +16645,12 @@ There are no restrictions on how the configuration scripts that Autoconf
|
||||
produces may be distributed or used. In Autoconf version 1, they were
|
||||
covered by the @acronym{GNU} General Public License. We still encourage
|
||||
software authors to distribute their work under terms like those of the
|
||||
GPL, but doing so is not required to use Autoconf.
|
||||
@acronym{GPL}, but doing so is not required to use Autoconf.
|
||||
|
||||
Of the other files that might be used with @command{configure},
|
||||
@file{config.h.in} is under whatever copyright you use for your
|
||||
@file{configure.ac}. @file{config.sub} and @file{config.guess} have an
|
||||
exception to the GPL when they are used with an Autoconf-generated
|
||||
exception to the @acronym{GPL} when they are used with an Autoconf-generated
|
||||
@command{configure} script, which permits you to distribute them under the
|
||||
same terms as the rest of your package. @file{install-sh} is from the X
|
||||
Consortium and is not copyrighted.
|
||||
@ -16975,7 +16915,7 @@ The creation of this cache can be disabled from
|
||||
details. You should be aware that disabling the cache slows down the
|
||||
Autoconf test suite by 40%. The more @acronym{GNU} Build System
|
||||
components are used, the more the cache is useful; for instance
|
||||
running @samp{autoreconf -f} on the Coreutils is twice slower without
|
||||
running @samp{autoreconf -f} on the Core Utilities is twice slower without
|
||||
the cache @emph{although @option{--force} implies that the cache is
|
||||
not fully exploited}, and eight times slower than without
|
||||
@option{--force}.
|
||||
|
||||
Loading…
x
Reference in New Issue
Block a user