Gpc

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5400 discussions

dispose: bug or feature?
by Russell Whitaker 11 Dec '07

11 Dec '07

Hi Given a pointer p, dispose(p) does not set p to nil. This program, program tst; type ptr = ^string; var p : ptr; begin p := new( ptr, 20 ); p^ := "abc"; writeln( p^ ); dispose( p ); p := nil; if p = nil then writeln("OK"); dispose( p ); writeln( p^ ); end. as is gives you abc OK segmentation fault The seg fault is from the last writeln. If you comment out the line "p := nil", the second "dispose" causes a core dump. If you comment out both "p := nil" and the second "dispose" you get abc abc and that's also an error. I do not know what side effects you might get if you caused "dispose" to set the pointer to nil. Russ

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Re: dispose: bug or feature?
by Scott Moore 11 Dec '07

11 Dec '07

Peter N Lewis wrote: > It's not worth nit picking on the list further, but I wonder if...: > >> dispose(q) >> shall remove the identifying-value denoted by the expression q from the >> pointer-type of q . It shall be an error if the identifying-value had >> been created using the form new(p,c l , . . .,cn). >> >> ... >> >> NOTE -- The removal of an identifying-value from the pointer-type to >> which it belongs renders the identified-variable inaccessible (see >> 6.5.4) and makes undefined all variables and functions that have that >> value attributed (see 6.6.3.2 and 6.8.2.2). > > > "identified-variable" refers to the content, not p per se? > > Note how it makes the distinction of "identifying-value" (ie the > pointer?) and "identified-variable" (ie p^). > > Thus p^ is inaccessible. > > There is a reason I don't attempt to read standards! It says "makes undefined all variables and functions that have that value attributed", and the "value" the speaketh of is the "identifying-value". This is why I included the definition of: new(p) shall create a new variable that is totally-undefined, shall create a new identifying-value of the pointer-type associated with p, that identifies the new variable, and shall attribute this identifying-value to the variable denoted by the variable-access p Note "shall attribute this identifying-value to the variable denoted by the variable-access p" The double speak has a purpose, and the meaning covers several storage management schemes, including references and recycling. For reference systems, where the pointer contains not an address but a logical key to the actual variable, the "identifying-value" becomes undefined because its table entry becomes invalid. For recycling systems, the actual pointer may be set invalid. Its an important point, because it lets the implementor implement advanced storage handling. Scott Moore

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German Book about GNU-Pascal needs contributors
by Eike 06 Dec '07

06 Dec '07

Hi Folks! There is a book in German language about GNU-Pascal available at Wikibooks. See http://de.wikibooks.org/wiki/GNU-Pascal_in_Beispielen There is a publishing company, who is going to sell this and some other books from wikibooks. The money will be donated to the wikimedia foundation. I do not have the time, to step through this book again and fix all those things, which might have changed or should be rewritten. If someone would like to take this job, feel free. Translators are also welcome. Without your help, this book becomes more and more outdated and not worth publishing. Yours Eike

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Updated review of GPC
by Scott Moore 27 Nov '07

27 Nov '07

I have completed a periodic update of a review for the GPC compiler with respect to its' ability to compile and run ISO 7185 level 0 standard programs. I present it here in advance of posting it on the web site: http://www.moorecad.com/standardpascal/compiler.html In order to give the members of the GPC group a chance to correct any errors or raise any complaints. You will please note that there is a section for GPC originator comments. I would be happy to accept any reasonable section the GPC group would wish to include in that section, limited only by size and taste concerns. I note that the web page for GPC does not specify who speaks for GPC, so I would only ask that if multiple people wish to post such a comment, the GPC group would work between its members to prepare a coordinated submittal. Thank you, Scott Moore <below contains the review> ======================================================================== GPC Last verified: November 25, 2007 ISO 7185 full standard test: One failure (see explanation) Version: gpc version 20051116, based on gcc-3.4.4 Pascal-s compile/run: Pass Implementation first order details: Processor run on: AMD Athlon 3200+ Bits: 32 Value of maxint: 2147483647 Default integer field width: 11 characters Default real format field width: 29 characters Default boolean field width: 6 Default character field width: 1 character. Implementation character set: ASCII My comments: 1. Test failure on ISO 7185 section 6.4.3.5, specifically the requirement that each line consist of a sequence of characters terminated by the eoln sequence. When a temporary (unnamed) file was output with an incomplete last line, and subsequently read back, the last eoln was found to be missing. The responsible parties for GPC have informed me that this problem has been fixed in the current version of GPC. When I am able to obtain and test that version, I will update this information. 2. The date of the version tested is fairly old (2005, above). The test was done using a "prebuilt" version of GPC (their terminology) from the GPC web site. The maintainers have recommended using a newer build of the source, which I didn't do for the following reasons. First, there is considerable effort involved with building GPC from source, and GPC is highly cross coupled to building GCC, itself a significant undertaking. Second, I don't believe most users would build their own new version, for similar reasons. Finally, the "current version" involves building from the current source with patches. It would be next to impossible for me to accurately specify such a "version" of the software. 3. The GPC documentation inaccurately states that the flag "--standard-pascal" is all that is needed to insure ISO 7185 level 0 compliance. In fact, this switch was found broken at the time of testing, and caused several normal ISO 7185 features to be incorrectly flagged as errors/warnings. In addition, the flag --field-widths was found to be needed. Finally, the version tested output several warnings with no relationship to Pascal (in fact, they were C language warnings). The net command syntax required to accurately compile ISO 7185 Pascal using GPC is: gpc --field-widths -Wno-warnings -o <program> <program>.pas Where <program> is the name of the Pascal program to be compiled. GPC originator comments: <Not supplied> =========================================================================

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unsubscribe
by jamiekg＠wizardling.geek.nz 27 Nov '07

27 Nov '07

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Most represented string in a TStringlist
by Contestcen＠aol.com 25 Nov '07

25 Nov '07

It looks like AOL may have converted my last message from plain text to HTML once again. Resending... Hi Is there an elegant way to determine which string is mostly represented in a TStringList? For instance if I've got the following the function should return 'Delphi': StringList[0] := 'Pascal'; StringList[1] := 'Pascal'; StringList[2] := 'Delphi'; StringList[3] := 'Delphi'; StringList[4] := 'Delphi'; - Wed, Nov 21 2007 1:04 pm 1 message, 1 author Probably the fastest way to do this is to hash each item to an integer and then count the occurrences of each hash value. Frank Rubin **************************************Check out AOL's list of 2007's hottest products. (http://money.aol.com/special/hot-products-2007?NCID=aoltop00030000000001)

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Most represented string in a TStringlist
by Contestcen＠aol.com 25 Nov '07

25 Nov '07

Hi Is there an elegant way to determine which string is mostly represented in a TStringList? For instance if I've got the following the function should return 'Delphi': StringList[0] := 'Pascal'; StringList[1] := 'Pascal'; StringList[2] := 'Delphi'; StringList[3] := 'Delphi'; StringList[4] := 'Delphi'; - Wed, Nov 21 2007 1:04 pm 1 message, 1 author Probably the fastest way to do this is to hash each item to an integer and then count the occurrences of each hash value. Frank Rubin **************************************Check out AOL's list of 2007's hottest products. (http://money.aol.com/special/hot-products-2007?NCID=aoltop00030000000001)

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ISO 7185 Failures [updated]
by Scott Moore 23 Nov '07

23 Nov '07

{****************************************************************************** GPC standard ISO 7185 test failures The following failures were found: =============================================================================== C:\GPC\usr\test>gpc --standard-pascal -Wno-warnings -o fails fails.pas fails.pas:115: error: ISO 7185 Pascal allows only simple constants fails.pas: In main program: fails.pas:136: error: this use of packed array components is an extension of fails.pas:136: error: Borland Pascal, traditional Macintosh Pascal fails.pas:137: error: this use of packed record fields is an extension of Borland fails.pas:137: error: Pascal, traditional Macintosh Pascal =============================================================================== None of these are valid failures, or indeed even have a reasonable explaination in the standard. Also, all of these used to work fine in GPC: GNU Pascal version 2.1 (20020510), based on gcc-2.95.3-6 (mingw special) See the testing details for that compiler: http://www.moorecad.com/standardpascal/compiler.html Now, with "--standard-pascal" off: =============================================================================== C:\GPC\usr\test>gpc -Wno-warnings -o fails fails.pas C:\GPC\usr\test>fails 1 10 100 2147483647 True False 'too much<eoln> too soon' s/b 'too much<eoln> too soon<eoln> ' =============================================================================== Items: 1. Integer field default appears to be "1". This appears to indicate the default fields for integer is set to 1. This is technically valid, but clearly preverts the intent of the language. The "Pascal users manual and report" shows several examples of the field for integer being clearly set to the maximum size of integer. Ie., for a maximum integer of 11 digits including the sign (for +/-2147483647) the default should be 11 digits for integer. The output of numbers in collumns under the assumption that they would correctly spaced for all integers would fail under the current GPC (see again the several examples in the "report"). I have had the discussion with another implementor, and this treatment of defaults falls under "techically valid (by the ISO 7185 standard), but would break examples of the original Pascal as formulated by Wirth", which I consider a quality issue. I tried this also with the "--standard-pascal" flag on (by commenting out the error causing statements), and got the same result. Again, this used to pass. 2. Boolean outputs nonstandard. There is no explaination for the values of boolean. Since they are treated as the strings "true" or "false", there is no possible default field that would deliver the results shown. If the default were 5 (size of 'false') the result would be: True False For 4 (size of 'true') it would be: True Fals I tried this also with the "--standard-pascal" flag on (by commenting out the error causing statements), and got the same result. Again, this used to pass. 3. Last line in file without "eoln" not corrected as required by standard. In ISO 7185 "6.4.3.5 File types" lines without proper eoln are referred to as "partial lines", and are stated not to occur. In effect, the implementation must either make sure that an eoln is always generated at the end of the file, or that on read, an eoln is essentially inserted if missing at the end of the file. In effect, a text file must be completely empty or be structured as a series of whole lines, including an eoln at the end of each line. I don't believe this ever passed in GPC, but I was told it would be fixed in later revisions. Here is a -v dump on the GPC used: =============================================================================== C:\GPC\usr\test>gpc -v Reading specs from /ecos-c/gpc/usr/bin/../lib/gcc/i686-pc-cygwin/3.4.4/specs Configured with: ../configure --verbose --prefix=/usr --exec-prefix=/usr --sysco nfdir=/etc --libdir=/usr/lib --libexecdir=/usr/lib --mandir=/usr/share/man --inf odir=/usr/share/info --enable-languages=c,pascal --enable-nls --without-included -gettext --enable-version-specific-runtime-libs --without-x --enable-libgcj --di sable-java-awt --with-system-zlib --enable-interpreter --disable-libgcj-debug -- enable-threads=posix --enable-java-gc=boehm --disable-win32-registry --enable-sj lj-exceptions --enable-hash-synchronization --enable-libstdcxx-debug Thread model: posix gpc version 20051116, based on gcc-3.4.4 =============================================================================== ******************************************************************************} program fails(output); const scst = 'this is a string'; type cset = set of char; prec = packed record i: integer; b: boolean; c: char; r: real; stc: cset; end; var i: integer; pavs: packed array [1..10] of cset; parec: prec; ft: text; ca: char; begin for i := 1 to 10 do pavs[i] := [chr(i+ord('a'))]; parec.stc := ['b'..'e', 'i']; writeln(1); writeln(10); writeln(100); writeln(maxint); writeln(true); writeln(false); rewrite(ft); writeln(ft, 'too much'); write(ft, 'too soon'); reset(ft); write(''''); while not eof(ft) do begin if eoln(ft) then write('<eoln>'); read(ft, ca); write(ca) end; write(''''); writeln(' s/b ''too much<eoln> too soon<eoln> '''); end.

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ISO 7185 test failures
by Scott Moore 23 Nov '07

23 Nov '07

{****************************************************************************** GPC standard ISO 7185 test failures The following failures were found: =============================================================================== C:\GPC\usr\test>gpc --standard-pascal -Wno-warnings -o fails fails.pas fails.pas:93: error: ISO 7185 Pascal allows only simple constants fails.pas: In main program: fails.pas:112: error: this use of packed array components is an extension of fails.pas:112: error: Borland Pascal, traditional Macintosh Pascal fails.pas:113: error: this use of packed record fields is an extension of Borland fails.pas:113: error: Pascal, traditional Macintosh Pascal =============================================================================== None of these are valid failures, or indeed even have a reasonable explaination in the standard. Also, all of these used to work fine in GPC: GNU Pascal version 2.1 (20020510), based on gcc-2.95.3-6 (mingw special) See the testing details for that compiler: http://www.moorecad.com/standardpascal/compiler.html Now, with "--standard-pascal" off: =============================================================================== C:\GPC\usr\test>gpc -Wno-warnings -o fails fails.pas C:\GPC\usr\test>fails 1 10 100 2147483647 True False =============================================================================== This appears to indicate the default fields for integer is set to 1. This is technically valid, but clearly preverts the intent of the language. The "Pascal users manual and report" shows several examples of the field for integer being clearly set to the maximum size of integer. Ie., for a maximum integer of 11 digits including the sign (for +/-2147483647) the default should be 11 digits for integer. The output of numbers in collumns under the assumption that they would correctly spaced for all integers would fail under the current GPC (see again the several examples in the "report"). I have had the discussion with another implementor, and this treatment of defaults falls under "techically valid (by the ISO 7185 standard), but would break examples of the original Pascal as formulated by Wirth", which I consider a quality issue. There is no explaination for the values of boolean. Since they are treated as the strings "true" or "false", there is no possible default field that would deliver the results shown. If the default were 5 (size of 'false') the result would be: True False For 4 (size of 'true') it would be: True Fals I tried this also with the "--standard-pascal" flag on (by commenting out the error causing statements), and got the same result. Again, this used to pass: GNU Pascal version 2.1 (20020510), based on gcc-2.95.3-6 (mingw special) Here is a -v dump on the GPC used: =============================================================================== C:\GPC\usr\test>gpc -v Reading specs from /ecos-c/gpc/usr/bin/../lib/gcc/i686-pc-cygwin/3.4.4/specs Configured with: ../configure --verbose --prefix=/usr --exec-prefix=/usr --sysco nfdir=/etc --libdir=/usr/lib --libexecdir=/usr/lib --mandir=/usr/share/man --inf odir=/usr/share/info --enable-languages=c,pascal --enable-nls --without-included -gettext --enable-version-specific-runtime-libs --without-x --enable-libgcj --di sable-java-awt --with-system-zlib --enable-interpreter --disable-libgcj-debug -- enable-threads=posix --enable-java-gc=boehm --disable-win32-registry --enable-sj lj-exceptions --enable-hash-synchronization --enable-libstdcxx-debug Thread model: posix gpc version 20051116, based on gcc-3.4.4 =============================================================================== ******************************************************************************} program fails(output); const scst = 'this is a string'; type cset = set of char; prec = packed record i: integer; b: boolean; c: char; r: real; stc: cset; end; var i: integer; pavs: packed array [1..10] of cset; parec: prec; begin for i := 1 to 10 do pavs[i] := [chr(i+ord('a'))]; parec.stc := ['b'..'e', 'i']; writeln(1); writeln(10); writeln(100); writeln(maxint); writeln(true); writeln(false) end.

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About Timing Functions and Inline Assembly
by pascaltomath＠yahoo.fr 16 Nov '07

16 Nov '07

Dear Kevan; Of course I do not know what scientific projects you are working on, but I guess that you also, you can probably use for your goals the "Inline Assembly" for Timing. As you know very well, with the Assembly opcode, or, with the Hex code, you can easily get the the timing in nanosecond unit. I use it for profiling my codings [for testing my: -vectorization, -pipelining, -unrolling, -overlapping, -recurrence processes], and, it proves itself very useful. And please, as you are a physicist, would you like not to forget to tell us if; according to the quantum physics laws, we in fact are living truly in a bi-dimensional holographic universe. Sincerely, Kadir T. --------------------------------- Ne gardez plus qu'une seule adresse mail ! Copiez vos mails vers Yahoo! Mail

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Gpc