Re: Why many programmers don't like GC?
On Friday, 15 January 2021 at 07:35:00 UTC, H. S. Teoh wrote: (1) Refactored one function called from an inner loop to reuse a buffer instead of allocating a new one each time, thus eliminating a large amount of garbage from small allocations; <...> The result was about 40-50% reduction in runtime, which is close to about a 2x speedup. I think this message needs to be signal boosted. Most of the time GC is not the problem. The problem is sloppy memory usage. If you allocate a lot of temporary objects your performance will suffer even if you use malloc and free. If you write code that tries to use stack allocation as much as possible, doesn't copy data around, reuses buffers then it will be faster than manual memory management that doesn't do that. And thats with a "slow" GC.
Re: Why many programmers don't like GC?
On Wednesday, 13 January 2021 at 18:58:56 UTC, Marcone wrote: I've always heard programmers complain about Garbage Collector GC. But I never understood why they complain. What's bad about GC? Most people get to know GC trough Java or C#. Those languages promote the use of OOP and they say that you dont need to worry about memory management. The result is that people write code that doesnt utilize CPU caches effectively and makes a lot of temporary allocations. For example people at Microsoft implemented json parser in C# and it would allocate 8GB of memory for every 1GB parsed. Add to that virtual machines and you find that programs written in those languages run like they are coded in molasse. People with experience of those programs conclude that is all because of GC. And its simple explanation for simple people.
Re: Why many programmers don't like GC?
On Friday, 15 January 2021 at 15:18:31 UTC, IGotD- wrote: I have a feeling that bump the pointer is not the complete algorithm that D uses because of that was the only one, D would waste a lot of memory. Freeing memory is for loosers :D https://issues.dlang.org/show_bug.cgi?id=21248 DMD allocates and never frees.
Re: Why many programmers don't like GC?
On Friday, 15 January 2021 at 14:35:55 UTC, Ola Fosheim Grøstad wrote: On Friday, 15 January 2021 at 14:24:40 UTC, welkam wrote: You can use GC with D compiler by passing -lowmem flag. I didnt measure but I heard it can increase compilation time by 3x. Thanks for the info. 3x is a lot Take it with a grain of salt. I heard it long time ago so I might not remember correctly and I didnt measure it myself. improved with precise collection Precise GC is slower than default GC. Making it use automatic garbage collection (of some form) would be an interesting benchmark. -lowmem flag replaces all* allocations with GC allocations so you can benchmark that On Friday, 15 January 2021 at 14:59:18 UTC, Ola Fosheim Grøstad wrote: I think? Or maybe I am missing something? A write barrier is a peace of code that is inserted before a write to an [object]. Imagine you have a class that has pointer to another class. If you want to change that pointer you need to tell the GC that you changed that pointer so GC can do its magic. https://en.wikipedia.org/wiki/Write_barrier#In_Garbage_collection 3. Make slices and dynamic arrays RC. Reference counting needs mutation. How do you define immutable RC slice that needs to mutate its reference count? Thats a unsolved problem in D.
Re: Why many programmers don't like GC?
On Thursday, 14 January 2021 at 18:51:16 UTC, Ola Fosheim Grøstad wrote: One can follow the same kind of reasoning for D. It makes no sense for people who want to stay high level and do batch programming. Which is why this disconnect exists in the community... I think. The reasoning of why we do not implement write barriers is that it will hurt low level programming. But I feel like if we drew a ven diagram of people who rely on GC and those who do a lot of writes trough a pointer we would get almost no overlap. In other words if D compiler had a switch that turned on write barriers and better GC I think many people would use it and find the trade offs acceptable.
Re: Why many programmers don't like GC?
On Friday, 15 January 2021 at 11:28:55 UTC, Ola Fosheim Grøstad wrote: On Friday, 15 January 2021 at 11:11:14 UTC, Mike Parker wrote: That's the whole point of being able to mix and match. Anyone avoiding the GC completely is missing it (unless they really, really, must be GC-less). Has DMD switched to using the GC as the default? No. And it will never will. Currently DMD uses custom allocator for almost everything. It works as follows. Allocate a big chunk(1MB) of memory using malloc. Have a internal pointer that points to the beginning of unallocated memory. When someone ask for memory return that pointer and increment internal pointer with the 16 byte aligned size of allocation. Meaning the new pointer is pointing to unused memory and everything behind the pointer has been allocated. This simple allocation strategy is called bump the pointer and it improved DMD performance by ~70%. You can use GC with D compiler by passing -lowmem flag. I didnt measure but I heard it can increase compilation time by 3x. https://github.com/dlang/dmd/blob/master/src/dmd/root/rmem.d#L153
Re: Should a parser type be a struct or class?
Oh an also https://github.com/dlang/dmd/pull/9899
Re: Should a parser type be a struct or class?
On Wednesday, 17 June 2020 at 14:32:09 UTC, Adam D. Ruppe wrote: On Wednesday, 17 June 2020 at 14:24:01 UTC, Stefan Koch wrote: Parser in dmd does even inherit from Lexer. why would a parser ever inherit from a lexer? So you can write nextToken() instead of lexer.nextToken()
32 bit phobos
I tried to compile a 32 bit executable but my system does not have 32 bit phobos. How do I get 32 bit phobos? I am using Manjaro. dmd -m32 source/test2.d /usr/bin/ld: skipping incompatible /usr/lib/gcc/x86_64-pc-linux-gnu/10.1.0/../../../libphobos2.a when searching for -lphobos2 /usr/bin/ld: skipping incompatible /usr/lib/libphobos2.a when searching for -lphobos2 /usr/bin/ld: cannot find -lphobos2 collect2: error: ld returned 1 exit status Error: linker exited with status 1
Re: I want Sublime 3 D auto import !
On Tuesday, 2 June 2020 at 06:00:10 UTC, Виталий Фадеев wrote: On Monday, 1 June 2020 at 18:55:03 UTC, Paul Backus wrote: On Monday, 1 June 2020 at 16:18:44 UTC, Виталий Фадеев wrote: I do it! https://github.com/vitalfadeev/SublimeDlangAutoImport Cool. I dont use classe but I see how this kind of functionality might be useful for other symbols.
Re: Mir Slice Column or Row Major
On Wednesday, 27 May 2020 at 16:53:37 UTC, jmh530 wrote: Not always true...many languages support column-major order (Fortran, most obviously). if your column major matrix is implemented as matrix[row_index][column_index] then ok no puppies will be hurt. But I dont see much value in such implementations.
Re: Mir Slice Column or Row Major
On Wednesday, 27 May 2020 at 01:31:23 UTC, data pulverizer wrote: column major Cute puppies die when people access their arrays in column major.
Re: How to get the pointer of "this" ?
On Sunday, 24 May 2020 at 17:05:16 UTC, Vinod K Chandran wrote: cast(DWORD_PTR) this); Where is DWORD_PTR defined? I cant find it in docs. If its an alias of long then you have to cast to a pointer like this cast(long*) this; you need to specify that you want to cast to a pointer of type T. In this case T is long.
Re: How to allocate/free memory under @nogc
There is automem to help with manual memory management https://code.dlang.org/packages/automem
Re: How to use this forum ?
On Wednesday, 20 May 2020 at 20:49:52 UTC, Vinod K Chandran wrote: Hi all, I have some questions about this forum. 1. How to edit a post ? 2. How to edit a reply ? 3. How to add some code(mostly D code) in posts & replies. 4. How to add an image in posts & replies. 5. Is there a feature to mark my post as "[SOLVED]" ? This is not a forum but a frontend to a mailing list. Since you cant edit sent emails you cant do 1, 2 and 5. if you want to add code then post it in a message if its short. If not try using github gist.
Re: large Windows mingw64 project in C99 --- need ABI compatible D compiler
On Wednesday, 20 May 2020 at 18:53:01 UTC, NonNull wrote: Which D compiler should be used to be ABI compatible with mingw32? And which to be ABI compatible with mingw64? I am not expert here but doesnt all C compilers have the same ABI? If yes then compile your code in 32 bits for 32 bit C obj files. If you are on 64 bit OS then D compilers will produce 64 bit executables by default. To change that use https://dlang.org/dmd-linux.html#switch-m32
Re: Is it possible to write some class members in another module ?
On Wednesday, 20 May 2020 at 17:29:47 UTC, Vinod K Chandran wrote: I am very sad that i delayed to start learning D only because of semicolons and curly braces. Walter(creator of this language) said that redundant grammar is a good thing because it allows compiler to emit better error messages.
Re: Is it possible to write some class members in another module ?
On Wednesday, 20 May 2020 at 09:45:48 UTC, Vinod K Chandran wrote:
// Now, we need to use like this
auto form= new Window();
form.event.click = bla_bla;
// I really want to use like this
auto form= new Window();
form.click = bla_bla;
```
Then you want alias this.
class Window : Control{
Events event;
alias event this
.
}
and now when you write
form.click = bla_bla;
Compiler first checks if form.click compiles and if it doesnt it
then it tries form.event.click
Re: Beginner's Comparison Benchmark
On Tuesday, 5 May 2020 at 20:29:13 UTC, Steven Schveighoffer wrote: the optimizer recognizes what you are doing and changes your code to: writeln(1_000_000_001); Oh yes a classic constant folding. The other thing to worry about is dead code elimination. Walter has a nice story where he sent his compiler for benchmarking and the compiler figured out that the the result of the calculation in benchmark is not used so it deleted the whole benchmark.
Re: How can I open a Binary EXE with Hexadecimal?
On Saturday, 2 May 2020 at 21:05:32 UTC, Baby Beaker wrote:
I need open a Binary EXE, it can be using "rb" mode and convert
it to Hexadecimal for me make some changes and save as "rb"
again. How can I make it? Thank you.
You dont convert binary data to hexadecimal. You display it as
hexadecimal. If you want to print file contents to console in hex
do something like this.
import std.stdio;
import std.algorithm;
auto fd = File("filename", "r"); //open file for reading
ubyte[] data; //a GC allocated buffer for data
fd.rawRead(data); //read the data
data[0..50].each!(n => stdout.writef("%X ",n));
/*take 50 elements from array and for each of them call lambda
that converts ubyte to string in hex format and prints to the
stdout*/
if you want to assign to this data you can do something like this
data[0] = Oxff;
And then write to file
Re: Newbie linker errors - still missing _fltused _tls_index _tls_used localtime tzset mainCRTStartup
If I remember correctly VS studio has different release and debug configurations for both compiler and linker. If release works but debug doesnt make sure that when you add things to one to also add to another
Re: Using shared memory and thread
On Monday, 4 November 2019 at 19:53:29 UTC, bioinfornatics wrote: 3/ variable flagged as `shared` does at mean the variable is put into L2 cache ? First caching is controlled by CPU not programmer. Second not all architectures share L2 between cores. 4 jaguar cores share L2 cache in consoles https://images.anandtech.com/doci/6976/Screen%20Shot%202013-05-23%20at%2012.22.12%20AM_678x452.png 2 bulldozer cores share L2 cache in FX processors https://s3.amazonaws.com/hs-wordpress/wp-content/uploads/2017/12/13035240/bulldozer_021.jpg each zen core has its own L2 cache in Ryzen cpu's https://images.anandtech.com/doci/10591/HC28.AMD.Mike%20Clark.final-page-014.jpg Third your link to run.dlang is 404 While you cant control cache contents explicitly you can control it by changing memory access patterns. When you fetch a peace of data CPU will load 64 byte size bucket/chunk that contains your data into L1 cache. Since L1 cache size is limited CPU had to remove existing data from L1 based on its eviction policy. Evicted data goes into L2 cache. That is the way to control what is where. By default all variables(except immutable or static) are thread local and can only be accessed by one thread. Shared keyword makes data accessible trough multiple threads
Re: Eliding of slice range checking
On Thursday, 24 October 2019 at 21:02:03 UTC, Per Nordlöw wrote: On Thursday, 24 October 2019 at 18:37:05 UTC, welkam wrote: I remember in some video Chandler Carruth said that value range propagation across function boundary was implemented in llvm but later removed because it produced no performance improvement for C and C++ code. I wonder how it fare when used on D code. Interesting. What uses of VRP do you see in D? Now that you asked I realized that it wont be that much useful because in D all arrays go together with their size so cross function VRP would do little.
Re: Eliding of slice range checking
On Wednesday, 23 October 2019 at 11:20:59 UTC, Per Nordlöw wrote:
Does DMD/LDC avoid range-checking in slice-expressions such as
the one in my array-overload of `startsWith` defined as
bool startsWith(T)(scope const(T)[] haystack,
scope const(T)[] needle)
{
if (haystack.length >= needle.length)
{
return haystack[0 .. needle.length] == needle; // is
slice range checking avoid here?
}
return false;
}
///
@safe pure nothrow @nogc unittest
{
auto x = "beta version";
assert(x.startsWith("beta"));
}
when building in release mode?
I remember a DMD pull from Ian Buclaw that enabled some eliding
but I don't remember if it includes the case above.
How can I investigate the codegen myself here?
I remember in some video Chandler Carruth said that value range
propagation across function boundary was implemented in llvm but
later removed because it produced no performance improvement for
C and C++ code. I wonder how it fare when used on D code.
Re: Remove unwanted ' \r ' from an Array ... by reading a *.txt file.
On Thursday, 24 October 2019 at 16:49:09 UTC, Mil58 wrote:
On Thursday, 24 October 2019 at 16:21:47 UTC, welkam wrote:
On Thursday, 24 October 2019 at 15:27:05 UTC, Mil58 wrote:
[...]
void main() {
File("data.txt", "r+")
.byLineCopy()
.array()
.each!writeln;
}
byLineCopy removes the new lines. If in the future you would
need the new line symbol call byLineCopy(Yes.keepTerminator)
Sorry but not working ... Surely i'm not able to insert and
adapt to my own script ! :-(
Could you, please, modify with the right syntax at the right
place ? - Thanks.
Ah sorry my bad. byLineCopy defaults to '\n' as line terminator
so it worked on my system.
import std.algorithm;
File("data.txt", "r+")
.byLineCopy(No.keepTerminator, '\r')
.joiner(" - ")
.writeln;
this will print the thing you wanted. If you want to capture that
value in a variable then
auto result = File("data.txt", "r+")
.byLineCopy(No.keepTerminator, '\r')
.joiner(" - ");
Re: [DTrace probe] is there a [portable] way to add section to elf executable?
On Wednesday, 23 October 2019 at 15:24:13 UTC, drug wrote: I'd like to add (and modify) section to ELF executable to implement DTrace probes. DTrace does it in probe assembly: ``` __asm__ __volatile__ ( "990: nop .pushsection .note.stapsdt,\"?\",\"note\" .balign 4 .4byte 992f-991f, 994f-993f, 3 991: .asciz \"stapsdt\" 992: .balign 4 993: .8byte 990b .8byte _.stapsdt.base .8byte 0 .asciz \"myapp\" .asciz \"func_call\" .asciz \"%n[_SDT_S1]@%[_SDT_A1] %n[_SDT_S2]@%[_SDT_A2]\" 994: .balign 4 .popsection" :: [_SDT_S1] "n" (SNIPPED_ONE), [_SDT_A1] "nor" ((a)), [_SDT_S2] "n" (SNIPPED_TWO), [_SDT_A2] "nor" ((b)) ); ``` So I need a way to add no op operation and define some data in `.note.stapsdt` section. This page https://dlang.org/spec/iasm.html does not contain any information about sections I hope you are not mixing up D SCRIPTING language that is used by Dtrace and D PROGRAMMING language. Second thing is that ELF format is used by Linux and other operating systems use different executable formats (mach-0 for macOs and PE for windows). So by definition its not portable. D's inline asm does not provide a way to modify *.obj files. It just insert your asm at that place.
Re: dub build doesn't work
On Thursday, 24 October 2019 at 01:17:24 UTC, OiseuKodeur wrote: BTW if you prefer using optlink and the digitalmars C runtime, you can instruct dub to do so with: --arch=x86 how can i add --arch=x86 flag to the dub.json so it do it automatically ? "dflags": [ "--arch=x86" ] This should work. Didnt tried though
Re: Converting a ulong to a byte array and constructing a ulong from it
On Thursday, 24 October 2019 at 14:08:36 UTC, 9898287 wrote: Does this contain any undefined behavior? It is in C as far as I knew. immutable int number = 1; auto bad_idea = (cast(ubyte*) )[0 .. number.sizeof]; bad_idea[0] = 2; writeln(number); //1 writeln(*(cast(int*)bad_idea.ptr)); //2 Cast is a powerful tool and with it you can destroy all type systems guarantees. In your case you will not have any problems just stay away from const and immutable
Re: Remove unwanted ' \r ' from an Array ... by reading a *.txt file.
On Thursday, 24 October 2019 at 15:27:05 UTC, Mil58 wrote:
Hi all It's me again ;-)
(because you're very strong in Dlang, here...)
In want a result as i write in a comment, with remove unwanted
'\r' >>
import std.stdio;
import std.file;
import std.conv;
import std.process : executeShell;
/* Content of 'values.txt' >>
abcd
1234
03b52h
*/
void main() {
auto fichier = File("values.txt", "r+");
string[] buffer;
foreach (line ; File("values.txt").byLine)
buffer ~= line.to!string;
writeln(buffer);
// Result: ["abcd\r", "1234\r", "03b52h"]
writeln(buffer[0], " - ", buffer[1], " - ", buffer[2]);
// Result: - 03b52h:-(
// Instead, i would : abcd - 1234 - 03b52h !!!
executeShell("pause");
fichier.close();
}
Thanks a lot, by advance :-)
void main() {
File("data.txt", "r+")
.byLineCopy()
.array()
.each!writeln;
}
byLineCopy removes the new lines. If in the future you would need
the new line symbol call byLineCopy(Yes.keepTerminator)
Re: gcc 9 vs. dmd?
On Friday, 30 November 2018 at 04:47:26 UTC, Andrew Pennebaker wrote: gcc is currently required for dmd on FreeBSD, as dmd links to libstdc++. Parts of dmd are still written in C++ but most of it was converted recently. More on that here: "DMD backend now in D" https://forum.dlang.org/thread/psaekt$tah$1...@digitalmars.com
Re: D is supposed to compile fast.
On Sunday, 25 November 2018 at 22:00:21 UTC, Chris Katko wrote:. So 1) I have to compile manually, then link. Except that also runs the files every time even if they're up-to-date. Is that normal behavior for C/C++? Well you dont have to use separate commands but yes compiling and linking are two steps and its normal behavior for all native languages. Each OS have their own linker and we dont control that. Two questions/topics/issues: --- #1 How to I only build files that are dirty? Do I actually need a build program like DUB, MAKE, or CMAKE to do that? (Can make, cmake be used?) How do they recognize files are out-dated if DMD can't? Is that just an industry-standard specialization/separation-of-responsibilities to not have the compiler auto-detect up-to-date builds? Yes its separation of responsibilities and there are many tools to automate that. Take a look at rdmd "rdmd recompiles files only on a needed basis, e.g. two invocations of rdmd in sequence without an intervening change to any relevant source file does not produce the executable again." https://dlang.org/rdmd.html If dub or rdmd doesnt satisfy your needs then you will need to learn other build system. I have to tell you that, as an outsider (who is VERY interested in D), this is very frustrating. "Compile times are fast" != "build times" is a huge misconception that borders on being a clever lie or twisting of words. When people hear "compile times", they think "time to compile the whole project" not "time to compile a simple test case that doesn't use any typical D features--also, it's not linking." Second, as shown here, it's not fast even for compiling! Because the second you touch std.regex (which has NO WARNINGS in the documentation), you're greeted with another clever lie-by-omission: a 10x explosion of build time over some modules. Yes D have some rough spots thats for sure. For compile times these include std.regex, std.format and heavy CTFE use. There is newCTFE engine that is faster but its not ready yet. That said D code compiles faster than C++ and Rust. To really put fast into perspective read this https://news.ycombinator.com/item?id=18442941 So my point is, I keep running into either misconceptions that conveniently make D look good, and other gotchas with NO DOCUMENTATION that make the language much slower to work with than expected. People who advertise languages talk about positives and leave out negatives. One thing you need to know - D doesnt have huge sponsor and some places might be rough because of it. Currently core dev team focus more on stability and bug fixes than build speeds. I think you rather have compiler that works than compiler that crashes 1 sec faster. Its not all negatives with regex. Current regex implementation is one of the fastest in the world. Thats classic D trade of - you spend compile time for better runtime. I mean, can you think of any module in the Python/Javascript/C# standard library that simply including it will swell your program to the point it can't compile? Have you tried C++ boost?
Re: D is supposed to compile fast.
On Friday, 23 November 2018 at 08:57:57 UTC, Chris Katko wrote: D is supposed to compile fast. You didnt read the fine print. It compiles simple code fast. Also compilation is separate step from linking and your program might spend half of "compilation" time in link phase.
Re: Why does nobody seem to think that `null` is a serious problem in D?
On Wednesday, 21 November 2018 at 09:20:01 UTC, NoMoreBugs wrote: On Tuesday, 20 November 2018 at 15:46:35 UTC, Adam D. Ruppe wrote: On Tuesday, 20 November 2018 at 13:27:28 UTC, welkam wrote: Because the more you learn about D the less you want to use classes. classes rock. You just initialize it. You're supposed to initialize *everything* anyway. a fan of classes...on the D forum? I don't get it. but of course you are right. classes do rock! In fact, there is not a better programming construct that I am aware of, the provides a better 'explicit' mapping from external objects to program constructs. Thank you Kristen and Ole-Johan. One thing that bugs me in programming is that in different programming languages the same things are named differently and things that are named the same are different. For example D`s slices and C#`s spans are the same thing. C++ string_view might be considered the same also, but classes in C++ and Java are not the same thing. In D classes are reference type and unless you mark them as final they will have vtable. Lets face it most people dont mark their classes as final. What all this mean is that EVERY access to class member value goes trough indirection (additional cost) and EVERY method call goes trough 2 indirections (one to get vtable and second to call function(method) from vtable). Now Java also have indirect vtable calls but it also have optimization passes that convert methods to final if they are not overridden. If Java didnt do that it would run as slow as Ruby. AFAIK D doesnt have such optimization pass. On top of that some people want to check on EVERY dereference if pointer is not null. How slow you want your programs to run? Thats negatives but what benefit classes give us? First being reference type its easy to move them in memory. That would be nice for compacting GC but D doesnt have compacting GC. Second they are useful for when you need to run code that some one else wrote for your project. Something like plugin system. [sarcasm]This is happening everyday[/sarcasm] Third porting code from Java to D. Everything else you can do with struct and other D features.
Re: Why does nobody seem to think that `null` is a serious problem in D?
On Monday, 19 November 2018 at 21:23:31 UTC, Jordi Gutiérrez Hermoso wrote: Why does nobody seem to think that `null` is a serious problem in D? Because the more you learn about D the less you want to use classes. I view class as compatibility feature when you want to port Java code to D. For regular code just use structs. For inheritance you could use alias, for polymorphism - templates etc. If you want to write OOP code you dont have to always start with keyword class. And since you dont use classes you dont view null as a high priority problem.
Re: What is best way to read and interpret binary files?
On Tuesday, 20 November 2018 at 12:01:49 UTC, Stanislav Blinov wrote: On Tuesday, 20 November 2018 at 11:54:59 UTC, welkam wrote: On Monday, 19 November 2018 at 22:14:25 UTC, Neia Neutuladh wrote: Nothing stops you from writing: SomeStruct myStruct; fd.rawRead((cast(ubyte*))[0..SomeStruct.sizeof]); Standard caveats about byte order and alignment. Never would I thought about casting struct to static array. If I understood correctly you cast myStruct pointer to ubyte pointer and then construct static array on stack with tmpArray.ptr = (ubyte pointer) and tmpArray.sizeof = SomeStruct.sizeof Almost correct, except it's not a static array, it's just a slice, i.e. ubyte[]. I guess it came from inseparability with C where you want to slice C arrays? Thats useful to know
Re: What is best way to read and interpret binary files?
On Monday, 19 November 2018 at 22:14:25 UTC, Neia Neutuladh wrote: Nothing stops you from writing: SomeStruct myStruct; fd.rawRead((cast(ubyte*))[0..SomeStruct.sizeof]); Standard caveats about byte order and alignment. Never would I thought about casting struct to static array. If I understood correctly you cast myStruct pointer to ubyte pointer and then construct static array on stack with tmpArray.ptr = (ubyte pointer) and tmpArray.sizeof = SomeStruct.sizeof What I figured out when I woke up is that I never needed c style arrays. What I could do is to allocate enough data for all file in ubyte array and just use slices to read data by chunks and cast them into necessary structs. Thanks Neia Neutuladh and H. S. Teoh for giving me some pointers https://www.explainxkcd.com/wiki/index.php/138:_Pointers
What is best way to read and interpret binary files?
So my question is in subject/title. I want to parse binary file
into D structs and cant really find any good way of doing it.
What I try to do now is something like this
byte[4] fake_integer;
auto fd = File("binary.data", "r");
fd.rawRead(fake_integer);
int real_integer = *(cast(int*) fake_integer.ptr);
What I ideally want is to have some kind of c style array and
just cast it into struct or take existing struct and populate
fields one by one with data from file. Is there a D way of doing
it or should I call core.stdc.stdio functions instead?
Re: Can opApply be made @nogc?
DIP 1000 says: Delegates currently defensively allocate closures with the GC. Few actually escape, and with scope only those that actually escape need to have the closures allocated. https://github.com/dlang/DIPs/blob/master/DIPs/DIP1000.md#benefits
Re: What does -vtls compiler flag does and ...
On Wednesday, 3 October 2018 at 21:50:49 UTC, Stanislav Blinov wrote: Thread-local storage is memory allocated for each thread. Only static non-immutable variables go there. Regular variables on the stack aren't explicitly placed in any TLS, they're, well, on the stack as it is. Oh so its like thread local globals sort of. My reasoning was that stack is a form of storage and is thread local so... Thanks for responses it became more clear what this flag does. Quick tests with different compilers. DMD from Arch repo compiles hello world (dmd -c main.d) in: ~0.1s DMD compiled with DMD and stock flags ~0.12s DMD compiled with ldc with -o2 ~0.35s DMD code gen is not that bad
Re: What does -vtls compiler flag does and ...
string a = "test"; is a variable that mutates so it should be thread local. Also ASM output shows that these variables are not optimized away so compiler should output something but it doesnt. Or I dont understand thread local storage.
Re: What does -vtls compiler flag does and ...
On Wednesday, 3 October 2018 at 20:58:01 UTC, Stanislav Blinov wrote: No, all *static non-immutable* variables are thread-local by default, not just "all variables". I misspoke but this should write something https://run.dlang.io/is/3u1wFp If you look at asm output there are "call _d_arraycatT@PLT32" instruction so those variables weren't optimized away and yet no output to stdout. If remove that flag ldc now compiles dmd but lacks optimizations so more work needs to be done.
What does -vtls compiler flag does and ...
I was playing around with dmd`s make file trying to see if I can compile dmd with different compilers and different compilation flags. By playing around I found that some dmd files are compiled with -vtls flag unconditionally and that ldc do not support this flag. First I dont know what -vtls flag does so I looked at documentation. DMD documentation says: -vtls List all variables going into thread local storage GDC documentation says: -fd-vtls Print information about all variables going into thread local storage to stdout. This doesnt help much. I still have no idea what it actually does. Aren't all variables thread local unless explicitly specified? So I tried to compile simple example and dmd printed nothing. GDC printed this: gdc: error: unrecognized command line option ‘-fd-vtls’ One gdc wiki(https://wiki.dlang.org/Using_GDC) is out of date and second I still have no clue what is does. This flag blocks compilation and I want to just remove it but since I dont know what it is used for I hesitate. If my attempts were to be successful in compiling dmd with other compilers I would make pull request but now I have more question than answers. What this flag does? Why some files compiled with it and other dont? Why it is added to all compilation targets unconditionally?
Setting up DMD on windows
Tried to use DMD compiler that I built from source by following these instructions https://wiki.dlang.org/Building_under_Windows They are outdated but I managed to compile it but I get this error when I tried to compile some code. dmdm -run Main.d C:\D\dmd2\windows\32\..\..\src\druntime\import\core\sys\windows\winbase.d(1828): Error: object.Error@(0): Access Violation 0x0064FED6 0x006502BE 0x006499CF 0x006488ED dmdm is just alias dmdm=C:\D\dmd2\windows\32\dmd.exe $* the compiler version is dmd-2.078.0 Could some one help fix this?
Re: How to proceed with learning to code Windows desktop applications?
On Monday, 29 January 2018 at 22:55:12 UTC, I Lindström wrote: The other way I've been thinking is to do the thing browser-based, but for some reason that doesn't feel right. Well it didnt felt wrong for Microsoft to use modified internet explorer to make calculator. You can read more on universal windows apps and XAML To learn GUI development first find GUI framework like GTK, QT etc. then watch and/or read tutorials on how to use them. For D language a list of libraries could be found here https://wiki.dlang.org/GUI_Libraries
Re: Looks like wrong error message
On Sunday, 28 January 2018 at 20:42:52 UTC, Jonathan M Davis wrote: There is nothing incorrect about the error message. The compiler looked at all of the functions in the overload set, and it found none that matched. The reason that it found none that matched was because it couldn't find any function template where those arguments passed the template constraint, and it tells you so. So, there is no bug here in the sense that the compiler is telling you the wrong thing. You can certainly open a bug report arguing that the error messages isn't human-friendly enough and suggest alternatives, and something along those lines may be implemented, but the message isn't actually wrong. So, feel free to open a bug report. However, you're not going to get an error message that says anything like "the arguments aren't the same type." The compiler doesn't understand what the template constraint means in "human terms." It just knows whether it's true or false, and in this case, if you provide arguments that don't have a common type that they implicitly convert to, then the template constraint will fail. But ultimately, you're going to have to read the template constraint and figure out why the arguments are failing. - Jonathan M Davis I would not complain if there were multiple functions just like error said. But the set contains only one making it not a set anymore and it says nothing about constraints. I downloaded dmd source. Might figure out something myself tomorrow
Looks like wrong error message
Error says that it cant deduce function from argument types but
in reality it fails to meet function template constraints. In
this case !is(CommonType!(staticMap!(ElementType,
staticMap!(Unqual, Ranges))) == void)
In human terms it means that arguments are not the same type. Is
this require bug report or it works as expected?
Code:
void main() {
import std.range : chain;
string s = "string";
auto arrayOfStrings = ["string"];
arrayOfStrings.chain(s);
}
error:
Main.d(9): Error: template std.range.chain cannot deduce function
from argument types !()(string[], string), candidates are:
C:\D\dmd2\windows\bin\..\..\src\phobos\std\range\package.d(894):
std.range.chain(Ranges...)(Ranges rs) if (Ranges.length > 0
&& allSatisfy!(isInputRange, staticMap!(Unqual, Ranges)) &&
!is(CommonType!(staticMap!(ElementType, staticMap!(Unqual,
Ranges))) == void))
Re: D generates large assembly for simple function
On Sunday, 28 January 2018 at 14:33:04 UTC, Johan Engelen wrote: Careful with these comparisons guys. Know what you are looking at. Wise words
Re: Writing a screen saver in D what libraries will help?
On Monday, 12 October 2015 at 19:16:10 UTC, Gary Willoughby wrote: If I was writing a screensaver in D what libraries are available for opening a window and drawing sprites, etc on it. GPU accelerated if possible. I'm using Ubuntu 14.04 and latest DMD compiler. You will need to interface to C libraries like SDL. There are bidings for it on DUB called derelict-sdl2
Re: How To: Passing curried functions around
Now its clearer to me. You want delegates http://wiki.dlang.org/Function_literals
Re: How to use ranges?
There was a talk on ranges in Dconf 2015 https://www.youtube.com/watch?v=A8Btr8TPJ8clist=PLEDeq48KhndP-mlE-0Bfb_qPIMA4RrrKoindex=10
