Search Results

Search found 5819 results on 233 pages for 'compiler theory'.

Page 169/233 | < Previous Page | 165 166 167 168 169 170 171 172 173 174 175 176  | Next Page >

  • Modify bash variables with sed

    - by Alexander Cska
    I am trying to modify a number of environmental variables containing predefined compiler flags. To do so, I tried using a bash loop that goes over all environmental variables listed with "env". for i in $(env | grep ipo | awk 'BEGIN {FS="="} ; { print $1 } ' ) do echo $(sed -e "s/-ipo/ / ; s/-axAVX/ /" <<< $i) done This is not working since the loop variable $i contains just the name of the environmental variable stored as a character string. I tried searching a method to convert a string into a variable but things started becoming unnecessary complicated. The basic problem is how to properly supply the environmental variable itself to sed. Any ideas how to properly modify my script are welcome. Thanks, Alex

    Read the article

  • How does SVN store commit time

    - by Salman
    I am working on a project that involves extracting details from a SVN server using SVNKit. My project is already complete and has been working we for a while now. During the testing, I noticed something rather very strange. the Commit Times my extract data seems is alway different from whats there in SVN Logs. I couldnt find any code in my project that could be inducing this difference but now I am looking as to how SVN server stores the Commit time in itself. As we have developer working from different part of the world thus resulting in different timezones, I was thinking that SVN might be storing time after converting them to GMT or timezone of the system on which SVN server is running. But that does not seem to be happening. Instead the times are stored as per the time when the commit was done and in that local timezone itself. I have been unable to find any substantial document on internet to support my theory so far. Can anybody in brief explain as how SVN store the Commit Time for each change? Documentaion links referring to this will be of great help.

    Read the article

  • floating constants in C

    - by Daziplqa
    Hi floks, I have a question concerning floating constants in C. In Java, the default type of floating point constants in double, so the following will causes a compilation error in java: float f = 100.0; // we either need to uses type case operator or put f at the end of the number constant. This is because the default floating-point constants are of type double and casting from double to float without type cast operator is an error, so we need either add a type case operator or put f at the end of the number. So, Why in C this doesn't produce an error, Is it because the default floating-point constants are of type float, or because the compiler do an implicit down-cast conversion (that doesn't requires type case operator in C)????

    Read the article

  • Appropriate uses of Monad `fail` vs. MonadPlus `mzero`

    - by jberryman
    This is a question that has come up several times for me in the design code, especially libraries. There seems to be some interest in it so I thought it might make a good community wiki. The fail method in Monad is considered by some to be a wart; a somewhat arbitrary addition to the class that does not come from the original category theory. But of course in the current state of things, many Monad types have logical and useful fail instances. The MonadPlus class is a sub-class of Monad that provides an mzero method which logically encapsulates the idea of failure in a monad. So a library designer who wants to write some monadic code that does some sort of failure handling can choose to make his code use the fail method in Monad or restrict his code to the MonadPlus class, just so that he can feel good about using mzero, even though he doesn't care about the monoidal combining mplus operation at all. Some discussions on this subject are in this wiki page about proposals to reform the MonadPlus class. So I guess I have one specific question: What monad instances, if any, have a natural fail method, but cannot be instances of MonadPlus because they have no logical implementation for mplus? But I'm mostly interested in a discussion about this subject. Thanks! EDIT: One final thought occured to me. I recently learned (even though it's right there in the docs for fail) that monadic "do" notation is desugared in such a way that pattern match failures, as in (x:xs) <- return [] call the monad's fail. It seems like the language designers must have been strongly influenced by the prospect of some automatic failure handling built in to haskell's syntax in their inclusion of fail in Monad.

    Read the article

  • Instance where embedded C++ compilers don't support multiple inheritance?

    - by Nathan
    I read a bit about a previous attempt to make a C++ standard for embedded platforms where they specifically said multiple inheritance was bad and thus not supported. From what I understand, this was never implemented as a mainstream thing and most embedded C++ compilers support most standard C++ constructs. Are there cases where a compiler on a current embedded platform (i.e. something not more than a few years old) absolutely does not support multiple inheritance? I don't really want to do multiple inheritance in a sense where I have a child with two full implementations of a class. What I am most interested in is inheriting from a single implementation of a class and then also inheriting one or more pure virtual classes as interfaces only. This is roughly equivalent to Java/.Net where I can extend only one class but implement as many interfaces as I need. In C++ this is all done through multiple inheritance rather than being able to specifically define an interface and declare a class implements it.

    Read the article

  • How do you make your Java application memory efficient?

    - by Boune
    How do you optimize the heap size usage of an application that has a lot (millions) of long-lived objects? (big cache, loading lots of records from a db) Use the right data type Avoid java.lang.String to represent other data types Avoid duplicated objects Use enums if the values are known in advance Use object pools String.intern() (good idea?) Load/keep only the objects you need I am looking for general programming or Java specific answers. No funky compiler switch. Edit: Optimize the memory representation of a POJO that can appear millions of times in the heap. Use cases Load a huge csv file in memory (converted into POJOs) Use hibernate to retrieve million of records from a database Resume of answers: Use flyweight pattern Copy on write Instead of loading 10M objects with 3 properties, is it more efficient to have 3 arrays (or other data structure) of size 10M? (Could be a pain to manipulate data but if you are really short on memory...)

    Read the article

  • How to speed up a slow UPDATE query

    - by Mike Christensen
    I have the following UPDATE query: UPDATE Indexer.Pages SET LastError=NULL where LastError is not null; Right now, this query takes about 93 minutes to complete. I'd like to find ways to make this a bit faster. The Indexer.Pages table has around 506,000 rows, and about 490,000 of them contain a value for LastError, so I doubt I can take advantage of any indexes here. The table (when uncompressed) has about 46 gigs of data in it, however the majority of that data is in a text field called html. I believe simply loading and unloading that many pages is causing the slowdown. One idea would be to make a new table with just the Id and the html field, and keep Indexer.Pages as small as possible. However, testing this theory would be a decent amount of work since I actually don't have the hard disk space to create a copy of the table. I'd have to copy it over to another machine, drop the table, then copy the data back which would probably take all evening. Ideas? I'm using Postgres 9.0.0. UPDATE: Here's the schema: CREATE TABLE indexer.pages ( id uuid NOT NULL, url character varying(1024) NOT NULL, firstcrawled timestamp with time zone NOT NULL, lastcrawled timestamp with time zone NOT NULL, recipeid uuid, html text NOT NULL, lasterror character varying(1024), missingings smallint, CONSTRAINT pages_pkey PRIMARY KEY (id ), CONSTRAINT indexer_pages_uniqueurl UNIQUE (url ) ); I also have two indexes: CREATE INDEX idx_indexer_pages_missingings ON indexer.pages USING btree (missingings ) WHERE missingings > 0; and CREATE INDEX idx_indexer_pages_null ON indexer.pages USING btree (recipeid ) WHERE NULL::boolean; There are no triggers on this table, and there is one other table that has a FK constraint on Pages.PageId.

    Read the article

  • I'm having a problem redeploying an applications using Drools and Tomcat 6

    - by FrankL
    I have a spring application that uses JBoss Drools 5. It works fine except for when I attempt to redeploy (i.e. hot deploy) the application after I make a change during development. It appears that tomcat keeps a lock on 2 drools jar files, drools-compiler-5.0.1.jar and drools-core-5.0.1.jar. Since they can't be deleted the new war file does not get deployed. If my application does not make any Drools logic calls, then the hot deploy works. Does anyone have any ideas?

    Read the article

  • How can I make this function act like an l-value?

    - by BeeBand
    Why can't I use the function ColPeekHeight() as an l-value? class View { public: int ColPeekHeight(){ return _colPeekFaceUpHeight; } void ColPeekHeight( int i ) { _colPeekFaceUpHeight = i; } private: int _colPeekFaceUpHeight; }; ... { if( v.ColPeekHeight() > 0.04*_heightTable ) v.ColPeekHeight()-=peek; } The compiler complains at v.ColPeekHeight()-=peek. How can I make ColPeekHeight() an l-value?

    Read the article

  • Option Value Changed - ODBC Error 2169

    - by fredrick-ughimi
    Hello Edgar, Thank you for your response. I am using Powerbasic (www.powerbasic.com) as my compiler and SQLTools as a third party tool to access ADS through ODBC. I must stat that this error also appers when I take other actions like Update, Delete, Find, etc. But I don't get this error when I am using MS Access. Here is my save routine: [Code] Local sUsername As String Local sPassword As String Local sStatus As String Local sSQLStatement1 As String sUsername = VD_GetText (nCbHndl, %ID_FRMUPDATEUSERS_TXTUSERNAME) If Trim$(sUsername) = "" Then MsgBox "Please, enter Username", %MB_ICONINFORMATION Or %MB_TASKMODAL, VD_App.Title Control Set Focus nCbHndl, %ID_FRMUPDATEUSERS_TXTUSERNAME Exit Function End If sPassword = VD_GetText (nCbHndl, %ID_FRMUPDATEUSERS_TXTPASSWORD) If Trim$(sPassword) = "" Then MsgBox "Please, enter Password", %MB_ICONINFORMATION Or %MB_TASKMODAL, VD_App.Title Control Set Focus nCbHndl, %ID_FRMUPDATEUSERS_TXTPASSWORD Exit Function End If sStatus = VD_GetText (nCbHndl, %ID_FRMUPDATEUSERS_CBOSTATUS) sSQLStatement1 = "INSERT INTO [tblUsers] (Username, Password, Status) " + _ "VALUES ('" + sUsername + "','" + sPassword + "','" + sStatus +"')" 'Submit the SQL Statement to the database SQL_Stmt %SQL_STMT_IMMEDIATE, sSQLStatement1 'Check for errors If SQL_ErrorPending Then SQL_MsgBox SQL_ErrorQuickAll, %MSGBOX_OK End If [/code] Best regards,

    Read the article

  • How does windows differentiate between regular exe and a .Net exe?

    - by Yogendra
    Hi All, This might be a duplicate entry. Excuse me if it is. I was asked in an interview as to how does Windows OS differentiate between regular exe and .Net exe. My reply was, when .Net exe is build, the compiler emits some information into the header. The information is PE32 or PE32+. windows verifies the header to determine if it needs to load the MSCOREE.dll which loads the CLR and executes the exe. I am not sure if my answer is correct ? Your inputs is appreciated.

    Read the article

  • Why "constructor-way" of declaring variable in "for-loop" allowed but in "if-statement" not allowed?

    - by PiotrNycz
    Consider this simple example: /*1*/ int main() { /*2*/ for (int i(7); i;){break;} /*3*/ if (int i(7)) {} /*4*/ } Why line-2 compiles just fine, whilst line-3 gives the error? This is little strange to me why if-statement is in this aspect treated worse than for-loop? If this is compiler specific - I tested with gcc-4.5.1: prog.cpp: In function 'int main()': prog.cpp:3:7: error: expected primary-expression before 'int' prog.cpp:3:7: error: expected ')' before 'int' I was inspired by this question [UPDATE] I know this compiles just fine: /*1*/ int main() { /*2*/ for (int i = 7; i;){break;} /*3*/ if (int i = 7) {} /*4*/ }

    Read the article

  • VB6 Parser/Lexer/Scripter

    - by rlb.usa
    I've got a game in VB6 and it works great and all, but I have been toying with the idea of creating a scripting engine. Ii'm thinking I'd like VB6 to read in flat text script files for me and then lex/parse/execute them. I have good programming experience, and I've built a simple C compiler, as well as a LOGO emulator before. My question is: Are there any tools that I can use, like Lexx/Yakk/Bison to help me? How should I approach this problem in regards to lexing, parsing, and feeding the commands back to VB6 so I can handle them? Is this idea a BAD IDEA in the sense that there are too many obstacles in the way (For example, building minesweeper in assembly, though not impossible, is very difficult, and a bad idea.)?

    Read the article

  • How does cast in C#/.NET 3.5 work for types with '?'

    - by Inez
    This is my code which works public decimal? Get() { var res = ... return res.Count() > 0 ? res.First() : (decimal?) null; } and this one doesn't work public decimal? Get() { var res = ... return res.Count() > 0 ? res.First() : null; } giving the compiler error: Error 1 Type of conditional expression cannot be determined because there is no implicit conversion between 'decimal' and '<null>' I wonder why? any ideas?

    Read the article

  • Global variable not stable after platform changed.

    - by user350555
    Our embedded system is built on a hw/sw platform made by enea. After the platform updated recently, we found some operations on the global variable keep crashing the system. For example, we have a global map structure holding some data. We can insert/iterate the map once or twice, then the address of the elements in the map suddenly changed to some forbidden addresses like 0x0 or 0x1d, the system just crash. The only different before/after the platform update is : 1) sw part: It's a c++ software and We changed the compiler from diab cc to gcc. 2) hw part: we have a new board, but the cpu is still powerpc405s. I tried every possible way but still can't figure out the reason. Any thoughts?

    Read the article

  • Behavior with primitive data types' value out of range & C99's PRI* macros

    - by Yktula
    Say we have an 8-bit unsigned integer n (UINT8_MAX=255); what is the behavior of the compiler for n=256? Where can I find a table of default behavior when the value of a data type is out of range for different data types? Is there a pattern to how they behave when set out of range? #include <stdio.h> #include <inttypes.h> uint8_t n = UINT8_MAX; int main() { printf("%hhu ",n++); printf("%hhu",n); return 0; } Compiling with gcc -std=c99 -Wall *.c, this prints: 255 0 Also, is it acceptable to use C99's PRI* macros? How are they named?

    Read the article

  • hiding inner class implementation using namespace

    - by Abruzzo Forte e Gentile
    Hi all I am developing a library and a would like to provide my users a public interface separate from the real implementatino that is hidden in a namespace. This way, I could change only the class HiddenQueue without changing myQueue that will be exposed to users only. If I put the C++ code of HiddenQueue in the myQueue.cpp file the compiler complains saying _innerQueue has incomplete type. I thought that the linker was able to resolve this. What I am doing wrong here? Thanks Afg // myQueue.h namespace inner{ class HiddenQueue; }; class myQueue{ public: myQueue(); ); private: inner::HiddenQueue _innerQueue; }; /////////////////////////// // myQueue.cpp namespace inner{ class HiddenQueue{}; };

    Read the article

  • Excess elements in scalar initializer

    - by Wade Williams
    I'm pretty noobish when it comes to C++ STL stuff. After a compiler upgrade, I'm getting: error: Semantic Issue: Excess elements in scalar initializer on the call: Certificate *tempcert; cValType( tempPerson->name, tempcert ); with a typedef of: typedef std::map< string, certificate* >::value_type cValType; I'm not certain what this error is telling me or how to fix it. (Ok, I realize it's telling me excess elements, but it looks like it matches the map prototype to me, so I'm confused.) Suggestions?

    Read the article

  • C++ app fails to initialize (0xc0000005), when using C# dll

    - by Simon
    Hi, I have a C# DLL, which I call from a native C++ programm. As I use Qt and /clr compiler option did not work I followed this tutorial for a bridge. So I have a VS2008 project (compiled with /clr), which links to the C# DLL and contains the bridge class and the native class, which exposes interfaces to my C++ programm. Another VS2008 project (no .net stuff) calls the native class (statically linked). I had some issues, but now the programm at least compiles. However, if I try to run this programm, I get a (0xc0000005) error on initialization, when I try to use the native class. As this happens on initialization, I don't even see, which DLLs fail to initialize. All DLLs should be in the right place. Any hints? Thank you.

    Read the article

  • Java class Class<T> and static method Class.forName() drive me crazy.

    - by matt
    Hi, this code doesn't compile. i'm wandering what i am doing wrong: private static Importable getRightInstance(String s) throws Exception { Class<Importable> c = Class.forName(s); Importable i = c.newInstance(); return i; } where Importable is an interface and the string s is the name of an implementing class. The compiler says: ./Importer.java:33: incompatible types found : java.lang.Class<capture#964 of ?> required: java.lang.Class<Importable> Class<Importable> c = Class.forName(format(s)); thanks for any help!

    Read the article

  • Compilation hangs for a class with field double d = 2.2250738585072012e-308

    - by 01es
    I have come across an interesting situation. A coworker committed some changes, which would not compile on my machine neither from the IDE (Eclipse) nor from a command line (Maven). The problem manifested in the compilation process taking 100% CPU and only killing the process would help to stop it. After some analysis the cause of the problem was located and resolved. It turned out be a line "double d = 2.2250738585072012e-308" (without semicolon at the end) in one of the interfaces. The following snipped duplicates it. public class WeirdCompilationIssue { double d = 2.2250738585072012e-308 } Why would compiler hang? A language edge case?

    Read the article

  • MySql "comments" parameter as descriptor?

    - by Nick
    So, I'm trying to learn a lot at once, and this place is really helpful! I'm making a little running log website for myself and maybe a few other people, and I have it so that the user can add workouts for each day. With each workout, I have a variety of information the user can fill out for the workout, such as running distance, time, quality of run, course, etc... I store this in a MySql database as a table with fields titled "distance", "time", "runquality", etc... Now, these field titles don't match up with what I want displayed on the running log, so I was thinking of using the "Comments" attribute for a field to store its human-readable title--thus the field "runquality" would have "Quality of run" as its comment, and then I would pull the comment with a SQL query and display it instead of the field name. Is this a good theoretical/practical way of going about it? And what sort of SQL would I use to pull the comment for the field anyway? Secondly, suppose I want to add the ability for the user to create their own workout descriptors. So say a user wants to add a "temperature" descriptor for their workout. Should I create a script that adds fields to my workout table, or should I create a separate table listing only workout descriptors and somehow link the descriptor table with the "contents" table? I haven't learned any theory about database design or anything so any help is appreciated!

    Read the article

  • C static variables and intialization

    - by yCalleecharan
    Hi, If I have a global static variable x like in this code #include <stdio.h> #include <stdio.h> static int x; int main(void) { DO SOMETHING WITH x HERE x++; } What will be difference if I opted to initialize x to a value first say as in static int x = 0; before entering "main"? In my first case where I didn't assign a value to x, does the compiler implicitly know that x is to be set to zero as it's a static variable? I heard that we can do this with static variables. Thanks a lot...

    Read the article

  • Is there a good collection library for C-language?

    - by matti
    We have to maintain and even develop C-code of our legacy system. Is there good collection library that would support Java/C# (new versions) style collections. Hashtable, HashSet, etc. Of course without objects, but with structs. The HashTable key limitations to "strings" and ints is not a problem. It wouldn't be bad if it's free even for commercial use. I'm back to C from C# and I must say i'm depressed using our own libraries and the language in general. We're using VS2005 and MS C-compiler if that has nothing to do with anything. Thanks & BR -Matti

    Read the article

  • In C#: How to declare a generic Dictionary with a type as key and an enumeration of that type as val

    - by Marcel
    Hi all, I want to declare a dictionary that stores typed IEnumerable's of a specific type, with that exact type as key, like so: (Edited to follow johny g's comment) private IDictionary<Type, IEnumerable<T>> _dataOfType where T: BaseClass; //does not compile! The concrete classes I want to store, all derive from BaseClass, therefore the idea to use it as constraint. The compiler complains that it expects a semicolon after the member name. If it would work, I would expect this would make the later retrieval from the dictionary simple like: IEnumerable<ConcreteData> concreteData; _sitesOfType.TryGetValue(typeof(ConcreteType), out concreteData); How to define such a dictionary?

    Read the article

< Previous Page | 165 166 167 168 169 170 171 172 173 174 175 176  | Next Page >