[Vm-dev] VM Maker: VMMaker.oscog-topa.2342.mcz

[Tobias Pape]

> On 06.03.2018, at 05:59, Eliot Miranda <eliot.miranda at gmail.com> wrote:
> 
> 
> Hi Tobias,
> 
>   but why?  Including configuration.h before including platform files can do nothing to modify those platform files, and can do nothing to modify their effects.  But including it after can at least modify their effects.  Can you explaining n why you want to include config.h before the platform includes?

Because config.h properly defines flags. 
One of those is _GNU_SOURCE, as explained in https://www.gnu.org/software/autoconf/manual/autoconf.html#Posix-Variants
Where the Autoconf macro AC_USE_SYSTEM_EXTENSIONS makes sure this is defined.

However, This must be one of the first things to define.

Also, I don't really see how the config.h (Either here
	https://github.com/OpenSmalltalk/opensmalltalk-vm/blob/Cog/platforms/unix/config/config.h.in
or in my branch
	https://github.com/OpenSmalltalk/opensmalltalk-vm/blob/krono/openbsd/platforms/unix/config/config.h.in
)
could alter anything AFTER system headers have been included.

Those "#undef"s will be changed to "#define"s if the proper measures took place.

In fact, it has to be the other way round, because config.h is also there to determine whether a system header is available in the first place.

For example, the system header sys/time.h is known not to be present everywhere.
(see https://github.com/OpenSmalltalk/opensmalltalk-vm/blob/krono/openbsd/platforms/unix/config/config.h.in#L209 )

So the pattern here is:

=-=-=-=-=-=-= myfile.c

#include "config.h"

#if defined(HAVE_SYS_TIME_H)
#include <sys/time.h>
#endif

=-=-=-=-=-=-= configure.ac (eg https://github.com/OpenSmalltalk/opensmalltalk-vm/blob/Cog/platforms/unix/config/configure.ac#L237)

AC_HEADER_TIME

=-=-=-=-=-=

Note that this is well documented for autoconf, eg especially things like time.h:

https://www.gnu.org/software/autoconf/manual/autoconf.html#index-AC_005fHEADER_005fTIME-654

But this is also true for all other HAVE_*_H in config.h{.in}, of which we actually already have a whooping 21 entries:

#undef	HAVE_INTERP_H
#undef	HAVE_UNISTD_H
#undef	HAVE_DIRENT_H
#undef	HAVE_SYS_NDIR_H
#undef	HAVE_SYS_DIR_H
#undef	HAVE_NDIR_H
#undef	HAVE_DLFCN_H
#undef	HAVE_ICONV_H
#undef	HAVE_SYS_TIME_H
#undef	HAVE_SYS_FILIO_H
#undef	HAVE_SYS_AUDIOIO_H
#undef	HAVE_SUN_AUDIOIO_H
#undef	HAVE_PTY_H
#undef	HAVE_UTIL_H
#undef	HAVE_LIBUTIL_H
#undef	HAVE_STROPTS_H
#undef	HAVE_GL_GL_H
#undef	HAVE_OPENGL_GL_H
#undef	NEED_SUNOS_H
#undef	HAVE_ALLOCA_H
#undef  HAVE_FEATURES_H

=-=-=-=

To come back to _GNU_SOURCE, this must be defined before including any system header, as it actually is checked the first time <features.h> is include, which every system header does. Including config.h after any system header has no effect whatsoever.

Best regards
	-Tobias


	

> 
> _,,,^..^,,,_ (phone)
> 
>> On Mar 5, 2018, at 6:06 PM, Tobias Pape <Das.Linux at gmx.de> wrote:
>> 
>> 
>> If someone could translate the source and commit it, I shall be very thankful :)
>> 
>> Best regards
>>   -Tobias
>> 
>>> On 06.03.2018, at 03:04, commits at source.squeak.org wrote:
>>> 
>>> 
>>> Tobias Pape uploaded a new version of VMMaker to project VM Maker:
>>> http://source.squeak.org/VMMaker/VMMaker.oscog-topa.2342.mcz
>>> 
>>> ==================== Summary ====================
>>> 
>>> Name: VMMaker.oscog-topa.2342
>>> Author: topa
>>> Time: 6 March 2018, 3:03:51.335169 am
>>> UUID: fea20583-2134-4dfa-bd3a-aa47504642a5
>>> Ancestors: VMMaker.oscog-akg.2341
>>> 
>>> The config should always come first.
>>> 
>>> =============== Diff against VMMaker.oscog-akg.2341 ===============
>>> 
>>> Item was changed:
>>> ----- Method: VMPluginCodeGenerator>>emitCHeaderOn: (in category 'C code generator') -----
>>> emitCHeaderOn: aStream
>>>   "Write a C file header onto the given stream."
>>> 
>>>   aStream nextPutAll: (self fileHeaderVersionStampForSourceClass: pluginClass).
>>>   aStream cr; cr.
>>> 
>>>   #('<math.h>' '<stdio.h>' '<stdlib.h>' '<string.h>' '<time.h>') reverseDo:
>>>       [:hdr| self addHeaderFileFirst: hdr].
>>> +    self addHeaderFileFirst: '"config.h"'. "Should always go first"
>>> 
>>>   "Additional header files; include C library ones first."
>>>   self emitHeaderFiles: (headerFiles select: [:hdr| hdr includes: $<]) on: aStream.
>>> 
>>>   aStream cr; nextPutAll:'/* Default EXPORT macro that does nothing (see comment in sq.h): */
>>> #define EXPORT(returnType) returnType
>>> 
>>> /* Do not include the entire sq.h file but just those parts needed. */
>>> #include "sqConfig.h"            /* Configuration options */
>>> #include "sqVirtualMachine.h"    /*  The virtual machine proxy definition */
>>> #include "sqPlatformSpecific.h"    /* Platform specific definitions */
>>> 
>>> #define true 1
>>> #define false 0
>>> #define null 0  /* using ''null'' because nil is predefined in Think C */
>>> #ifdef SQUEAK_BUILTIN_PLUGIN
>>> # undef EXPORT
>>> # define EXPORT(returnType) static returnType
>>> #endif'; cr; cr.
>>>   self addHeaderFile: '"sqMemoryAccess.h"'.
>>>   "Additional header files; include squeak VM ones last"
>>>   self emitHeaderFiles: (headerFiles reject: [:hdr| hdr includes: $<]) on: aStream.
>>>   self maybePutPreambleFor: pluginClass on: aStream.
>>>   aStream cr!
>>> 
>>