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• FILE_NOT_FOUND when trying to open COM port C++

  - by Moutabreath

  I am trying to open a com port for reading and writing using C++ but I can't seem to pass the first stage of actually opening it. I get an INVALID_HANDLE_VALUE on the handle with GetLastError FILE_NOT_FOUND. I have searched around the web for a couple of days I'm fresh out of ideas. I have searched through all the questions regarding COM on this website too. I have scanned through the existing ports (or so I believe) to get the name of the port right. I also tried combinations of _T("COM1") with the slashes, without the slashes, with colon, without colon and without the _T I'm using windows 7 on 64 bit machine. this is the code i got I'll be glad for any input on this void SendToCom(char* data, int len) { DWORD cbNeeded = 0; DWORD dwPorts = 0; EnumPorts(NULL, 1, NULL, 0, &cbNeeded, &dwPorts); //What will be the return value BOOL bSuccess = FALSE; LPCSTR COM1 ; BYTE* pPorts = static_cast<BYTE*>(malloc(cbNeeded)); bSuccess = EnumPorts(NULL, 1, pPorts, cbNeeded, &cbNeeded, &dwPorts); if (bSuccess){ PORT_INFO_1* pPortInfo = reinterpret_cast<PORT_INFO_1*>(pPorts); for (DWORD i=0; i<dwPorts; i++) { //If it looks like "COMX" then size_t nLen = _tcslen(pPortInfo->pName); if (nLen > 3) { if ((_tcsnicmp(pPortInfo->pName, _T("COM"), 3) == 0) ){ COM1 =pPortInfo->pName; //COM1 ="\\\\.\\COM1"; HANDLE m_hCommPort = CreateFile( COM1 , GENERIC_READ|GENERIC_WRITE, // access ( read and write) 0, // (share) 0:cannot share the COM port NULL, // security (None) OPEN_EXISTING, // creation : open_existing FILE_FLAG_OVERLAPPED, // we want overlapped operation NULL // no templates file for COM port... ); if (m_hCommPort==INVALID_HANDLE_VALUE) { DWORD err = GetLastError(); if (err == ERROR_FILE_NOT_FOUND) { MessageBox(hWnd,"ERROR_FILE_NOT_FOUND",NULL,MB_ABORTRETRYIGNORE); } else if(err == ERROR_INVALID_NAME) { MessageBox(hWnd,"ERROR_INVALID_NAME",NULL,MB_ABORTRETRYIGNORE); } else { MessageBox(hWnd,"unkown error",NULL,MB_ABORTRETRYIGNORE); } } else{ WriteAndReadPort(m_hCommPort,data); } } pPortInfo++; } } } }

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• urgent..haskell mini interpreter

  - by mohamed elshikh

  i'm asked to implement this project and i have problems in part b which is the eval function this is the full describtion of the project You are required to implement an interpreter for mini-Haskell language. An interpreter is dened in Wikipedia as a computer program that executes, i.e. performs, instructions written in a programming language. The interpreter should be able to evaluate functions written in a special notation, which you will dene. A function is dened by: Function name Input Parameters : dened as a list of variables. The body of the function. The body of the function can be any of the following statements: a) Variable: The function may return any of the input variables. b) Arithmetic Expressions: The arithmetic expressions include input variables and addition, sub- traction, multiplication, division and modulus operations on arithmetic expressions. c) Boolean Expressions: The Boolean expressions include the ordering of arithmetic expressions (applying the relationships: <, =<, , = or =) and the anding, oring and negation of Boolean expressions. d) If-then-else statements: where the if keyword is followed by a Boolean expression. The then and else parts may be followed by any of the statements described here. e) Guarded expressions: where each case consists of a boolean expression and any of the statements described here. The expression consists of any number of cases. The rst case whose condition is true, its body should be evaluated. The guarded expression has to terminate with an otherwise case. f) Function calls: the body of the function may have a call to another function. Note that all inputs passed to the function will be of type Int. The output of the function can be of type Int or Bool. To implement the interpreter, you are required to implement the following: a) Dene a datatype for the following expressions: Variables Arithmetic expressions Boolean expressions If-then-else statements Guarded expressions Functions b) Implement the function eval which evaluates a function. It takes 3 inputs: The name of a function to be evaluated represented as a string. A list of inputs to that function. The arguments will always be of datatype Int. A list of functions. Each function is represented as instance of the datatype that you have created for functions. c) Implement the function get_type that returns the type of the function (as a string). The input to this function is the same as in part b. here is what i've done data Variable = v(char) data Arth= va Variable | Add Arth Arth | Sub Arth Arth | Times Arth Arth | Divide Arth Arth data Bol= Great Arth Arth | Small Arth Arth | Geq Arth Arth | Seq Arth Arth | And Bol Bol | Or Bol Bol | Neg Bol data Cond = data Guard = data Fun =cons String [Variable] Body data Body= bodycons(String) |Bol |Cond |Guard |Arth

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• non blocking TCP-acceptor not reading from socket

  - by Abruzzo Forte e Gentile

  I have the code below implementing a NON-Blocking TCP acceptor. Clients are able to connect without any problem and the writing seems occurring as well, but the acceptor doesn't read anything from the socket and the call to read() blocks indefinitely. Am I using some wrong setting for the acceptor? Kind Regards AFG int main(){ create_programming_socket(); poll_programming_connect(); while(1){ poll_programming_read(); } } int create_programming_socket(){ int cnt = 0; p_listen_socket = socket( AF_INET, SOCK_STREAM, 0 ); if( p_listen_socket < 0 ){ return 1; } int flags = fcntl( p_listen_socket, F_GETFL, 0 ); if( fcntl( p_listen_socket, F_SETFL, flags | O_NONBLOCK ) == -1 ){ return 1; } bzero( (char*)&p_serv_addr, sizeof(p_serv_addr) ); p_serv_addr.sin_family = AF_INET; p_serv_addr.sin_addr.s_addr = INADDR_ANY; p_serv_addr.sin_port = htons( p_port ); if( bind( p_listen_socket, (struct sockaddr*)&p_serv_addr , sizeof(p_serv_addr) ) < 0 ) { return 1; } listen( p_listen_socket, 5 ); return 0; } int poll_programming_connect(){ int retval = 0; static socklen_t p_clilen = sizeof(p_cli_addr); int res = accept( p_listen_socket, (struct sockaddr*)&p_cli_addr, &p_clilen ); if( res > 0 ){ p_conn_socket = res; int flags = fcntl( p_conn_socket, F_GETFL, 0 ); if( fcntl( p_conn_socket, F_SETFL, flags | O_NONBLOCK ) == -1 ){ retval = 1; }else{ p_connected = true; } }else if( res == -1 && ( errno == EWOULDBLOCK || errno == EAGAIN ) ) { //printf( "poll_sock(): accept(c_listen_socket) would block\n"); }else{ retval = 1; } return retval; } int poll_programming_read(){ int retval = 0; bzero( p_buffer, 256 ); int numbytes = read( p_conn_socket, p_buffer, 255 ); if( numbytes > 0 ) { fprintf( stderr, "poll_sock(): read() read %d bytes\n", numbytes ); pkt_struct2_t tx_buf; int fred; int i; } else if( numbytes == -1 && ( errno == EWOULDBLOCK || errno == EAGAIN ) ) { //printf( "poll_sock(): read() would block\n"); } else { close( p_conn_socket ); p_connected = false; retval = 1; } return retval; }

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• Running daemon through rsh

  - by Max

  I want to run program as daemon in remote machine in Unix. I have rsh connection and I want the program to be running after disconnection. Suppose I have two programs: util.cpp and forker.cpp. util.cpp is some utility, for our purpose let it be just infinite root. util.cpp int main() { while (true) {}; return 0; } forker.cpp takes some program and run it in separe process through fork() and execve(): forker.cpp #include <stdio.h> #include <errno.h> #include <stdlib.h> #include <unistd.h> int main(int argc, char** argv) { if (argc != 2) { printf("./a.out <program_to_fork>\n"); exit(1); } pid_t pid; if ((pid = fork()) < 0) { perror("fork error."); exit(1); } else if (!pid) { // Child. if (execve(argv[1], &(argv[1]), NULL) == -1) { perror("execve error."); exit(1); } } else { // Parent: do nothing. } return 0; } If I run: ./forker util forker is finished very quickly, and bash 'is not paused', and util is running as daemon. But if I run: scp forker remote_server://some_path/ scp program remote_server://some_path/ rsh remote_server 'cd /some_path; ./forker program' then it is all the same (i.e. at the remote_sever forker is finishing quickly, util is running) but my bash in local machine is paused. It is waiting for util stopping (I checked it. If util.cpp is returning than it is ok.), but I don't understand why?! There are two questions: 1) Why is it paused when I run it through rsh? I am sure that I chose some stupid way to run daemon. So 2) How to run some program as daemon in C/C++ in unix-like platforms. Tnx!

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• Problem separating C++ code in header, inline functions and code.

  - by YuppieNetworking

  Hello all, I have the simplest code that I want to separate in three files: Header file: class and struct declarations. No implementations at all. Inline functions file: implementation of inline methods in header. Code file: normal C++ code for more complicated implementations. When I was about to implement an operator[] method, I couldn't manage to compile it. Here is a minimal example that shows the same problem: Header (myclass.h): #ifndef _MYCLASS_H_ #define _MYCLASS_H_ class MyClass { public: MyClass(const int n); virtual ~MyClass(); double& operator[](const int i); double operator[](const int i) const; void someBigMethod(); private: double* arr; }; #endif /* _MYCLASS_H_ */ Inline functions (myclass-inl.h): #include "myclass.h" inline double& MyClass::operator[](const int i) { return arr[i]; } inline double MyClass::operator[](const int i) const { return arr[i]; } Code (myclass.cpp): #include "myclass.h" #include "myclass-inl.h" #include <iostream> inline MyClass::MyClass(const int n) { arr = new double[n]; } inline MyClass::~MyClass() { delete[] arr; } void MyClass::someBigMethod() { std::cout << "Hello big method that is not inlined" << std::endl; } And finally, a main to test it all: #include "myclass.h" #include <iostream> using namespace std; int main(int argc, char *argv[]) { MyClass m(123); double x = m[1]; m[1] = 1234; cout << "m[1]=" << m[1] << endl; x = x + 1; return 0; } void nothing() { cout << "hello world" << endl; } When I compile it, it says: main.cpp:(.text+0x1b): undefined reference to 'MyClass::MyClass(int)' main.cpp:(.text+0x2f): undefined reference to 'MyClass::operator[](int)' main.cpp:(.text+0x49): undefined reference to 'MyClass::operator[](int)' main.cpp:(.text+0x65): undefined reference to 'MyClass::operator[](int)' However, when I move the main method to the MyClass.cpp file, it works. Could you guys help me spot the problem? Thank you.

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• Java program grading

  - by pasito15

  I've been working on this program for hours and I can't figure out how to get the program to actually print the grades from the scores Text file public class Assign7{ private double finalScore; private double private_quiz1; private double private_quiz2; private double private_midTerm; private double private_final; private final char grade; public Assign7(double finalScore){ private_quiz1 = 1.25; private_quiz2 = 1.25; private_midTerm = 0.25; private_final = 0.50; if (finalScore >= 90) { grade = 'A'; } else if (finalScore >= 80) { grade = 'B'; } else if (finalScore >= 70) { grade = 'C'; } else if (finalScore>= 60) { grade = 'D'; } else { grade = 'F'; } } public String toString(){ return finalScore+":"+private_quiz1+":"+private_quiz2+":"+private_midTerm+":"+private_final; } } this code compiles as well as this one import java.util.*; import java.io.*; public class Assign7Test{ public static void main(String[] args)throws Exception{ int q1,q2; int m = 0; int f = 0; int Record ; String name; Scanner myIn = new Scanner( new File("scores.txt") ); System.out.println( myIn.nextLine() +" avg "+"letter"); while( myIn.hasNext() ){ name = myIn.next(); q1 = myIn.nextInt(); q2 = myIn.nextInt(); m = myIn.nextInt(); f = myIn.nextInt(); Record myR = new Record( name, q1,q2,m,f); System.out.println(myR); } } public static class Record { public Record() { } public Record(String name, int q1, int q2, int m, int f) { } } } once a compile the code i get this which dosent exactly compute the numbers I have in the scores.txt Name quiz1 quiz2 midterm final avg letter Assign7Test$Record@4bcc946b Assign7Test$Record@642423 Exception in thread "main" java.until.InputMismatchException at java.until.Scanner.throwFor(Unknown Source) at java.until.Scanner.next(Unknown Source) at java.until.Scanner.nextInt(Unknown Source) at java.until.Scanner.nextInt(Unknown Source) at Assign7Test.main(Assign7Test.java:25)

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• bad file descriptor with close() socket (c++)

  - by user321246

  hi everybody! I'm running out of file descriptors when my program can't connect another host. The close() system call doesn't work, the number of open sockets increases. I can se it with cat /proc/sys/fs/file-nr Print from console: connect: No route to host close: Bad file descriptor connect: No route to host close: Bad file descriptor .. Code: #include <stdio.h> #include <stdlib.h> #include <sys/socket.h> #include <netinet/in.h> #include <netdb.h> #include <string.h> #include <iostream> using namespace std; #define PORT 1238 #define MESSAGE "Yow!!! Are we having fun yet?!?" #define SERVERHOST "192.168.9.101" void write_to_server (int filedes) { int nbytes; nbytes = write (filedes, MESSAGE, strlen (MESSAGE) + 1); if (nbytes < 0) { perror ("write"); } } void init_sockaddr (struct sockaddr_in *name, const char *hostname, uint16_t port) { struct hostent *hostinfo; name->sin_family = AF_INET; name->sin_port = htons (port); hostinfo = gethostbyname (hostname); if (hostinfo == NULL) { fprintf (stderr, "Unknown host %s.\n", hostname); } name->sin_addr = *(struct in_addr *) hostinfo->h_addr; } int main() { for (;;) { sleep(1); int sock; struct sockaddr_in servername; /* Create the socket. */ sock = socket (PF_INET, SOCK_STREAM, 0); if (sock < 0) { perror ("socket (client)"); } /* Connect to the server. */ init_sockaddr (&servername, SERVERHOST, PORT); if (0 > connect (sock, (struct sockaddr *) &servername, sizeof (servername))) { perror ("connect"); sock = -1; } /* Send data to the server. */ if (sock > -1) write_to_server (sock); if (close (sock) != 0) perror("close"); } return 0; }

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• Implementing default constructors

  - by James

  Implement the default constructor, the constructors with one and two int parameters. The one-parameter constructor should initialize the first member of the pair, the second member of the pair is to be 0. Overload binary operator + to add the pairs as follows: (a, b) + (c, d) = (a + c, b + d); Overload the - analogously. Overload the * on pairs ant int as follows: (a, b) * c = (a * c, b * c). Write a program to test all the member functions and overloaded operators in your class definition. You will also need to write accessor (get) functions for each member. The definition of the class Pairs: class Pairs { public: Pairs(); Pairs(int first, int second); Pairs(int first); // other members and friends friend istream& operator>> (istream&, Pair&); friend ostream& operator<< (ostream&, const Pair&); private: int f; int s; }; Self-Test Exercise #17: istream& operator (istream& ins, Pair& second) { char ch; ins ch; // discard init '(' ins second.f; ins ch; // discard comma ',' ins second.s; ins ch; // discard final '(' return ins; } ostream& operator<< (ostream& outs, const Pair& second) { outs << '('; outs << second.f; outs << ", " ;// I followed the Author's suggestion here. outs << second.s; outs << ")"; return outs; }

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• Function returning MYSQL_ROW

  - by Gabe

  I'm working on a system using lots of MySQL queries and I'm running into some memory problems I'm pretty sure have to do with me not handling pointers right... Basically, I've got something like this: MYSQL_ROW function1() { string query="SELECT * FROM table limit 1;"; MYSQL_ROW return_row; mysql_init(&connection); // "connection" is a global variable if (mysql_real_connect(&connection,HOST,USER,PASS,DB,0,NULL,0)){ if (mysql_query(&connection,query.c_str())) cout << "Error: " << mysql_error(&connection); else{ resp = mysql_store_result(&connection); //"resp" is also global if (resp) return_row = mysql_fetch_row(resp); mysql_free_result(resp); } mysql_close(&connection); }else{ cout << "connection failed\n"; if (mysql_errno(&connection)) cout << "Error: " << mysql_errno(&connection) << " " << mysql_error(&connection); } return return_row; } And function2(): MYSQL_ROW function2(MYSQL_ROW row) { string query = "select * from table2 where code = '" + string(row[2]) + "'"; MYSQL_ROW retorno; mysql_init(&connection); if (mysql_real_connect(&connection,HOST,USER,PASS,DB,0,NULL,0)){ if (mysql_query(&connection,query.c_str())) cout << "Error: " << mysql_error(&conexao); else{ // My "debugging" shows me at this point `row[2]` is already fubar resp = mysql_store_result(&connection); if (resp) return_row = mysql_fetch_row(resp); mysql_free_result(resp); } mysql_close(&connection); }else{ cout << "connection failed\n"; if (mysql_errno(&connection)) cout << "Error : " << mysql_errno(&connection) << " " << mysql_error(&connection); } return return_row; } And main() is an infinite loop basically like this: int main( int argc, char* args[] ){ MYSQL_ROW row = NULL; while (1) { row = function1(); if(row != NULL) function2(row); } } (variable and function names have been generalized to protect the innocent) But after the 3rd or 4th call to function2, that only uses row for reading, row starts losing its value coming to a segfault error... Anyone's got any ideas why? I'm not sure the amount of global variables in this code is any good, but I didn't design it and only got until tomorrow to fix and finish it, so workarounds are welcome! Thanks!

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• .NET Free memory usage (how to prevent overallocation / release memory to the OS)

  - by Ronan Thibaudau

  I'm currently working on a website that makes large use of cached data to avoid roundtrips. At startup we get a "large" graph (hundreds of thouthands of different kinds of objects). Those objects are retrieved over WCF and deserialized (we use protocol buffers for serialization) I'm using redgate's memory profiler to debug memory issues (the memory didn't seem to fit with how much memory we should need "after" we're done initializing and end up with this report Now what we can gather from this report is that: 1) Most of the memory .NET allocated is free (it may have been rightfully allocated during deserialisation, but now that it's free, i'd like for it to return to the OS) 2) Memory is fragmented (which is bad, as everytime i refresh the cash i need to redo the memory hungry deserialisation process and this, in turn creates large object that may throw an OutOfMemoryException due to fragmentation) 3) I have no clue why the space is fragmented, because when i look at the large object heap, there are only 30 instances, 15 object[] are directly attached to the GC and totally unrelated to me, 1 is a char array also attached directly to the GC Heap, the remaining 15 are mine but are not the cause of this as i get the same report if i comment them out in code. So my question is, what can i do to go further with this? I'm not really sure what to look for in debugging / tools as it seems my memory is fragmented, but not by me, and huge amounts of free spaces are allocated by .net , which i can't release. Also please make sure you understand the question well before answering, i'm not looking for a way to free memory within .net (GC.Collect), but to free memory that is already free in .net , to the system as well as to defragment said memory. Note that a slow solution is fine, if it's possible to manually defragment the large heap i'd be all for it as i can call it at the end of RefreshCache and it's ok if it takes 1 or 2 second to run. Thanks for your help! A few notes i forgot: 1) The project is a .net 2.0 website, i get the same results running it in a .net 4 pool, idem if i run it in a .net 4 pool and convert it to .net 4 and recompile. 2) These are results of a release build, so debug build can not be the issue. 3) And this is probably quite important, i do not get these issues at all in the webdev server, only in IIS, in the webdev i get memory consumption rather close to my actual consumption (well more, but not 5-10X more!)

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• How to return the value from MySql Stored Proc ??

  - by karthik

  I am using the below storedproc to generate the Insert statements of a specified table It is build-ed without any errors. Now i want to return the result set in "V_string" as output of the SP DELIMITER $$ DROP PROCEDURE IF EXISTS `demo`.`InsertGenerator` $$ CREATE DEFINER=`root`@`localhost` PROCEDURE `InsertGenerator`() SWL_return: BEGIN -- SQLWAYS_EVAL# to retrieve column specific information -- SQLWAYS_EVAL# table DECLARE v_string NATIONAL VARCHAR(3000); -- SQLWAYS_EVAL# first half -- SQLWAYS_EVAL# tement DECLARE v_stringData NATIONAL VARCHAR(3000); -- SQLWAYS_EVAL# data -- SQLWAYS_EVAL# statement DECLARE v_dataType NATIONAL VARCHAR(1000); -- SQLWAYS_EVAL# -- SQLWAYS_EVAL# columns DECLARE v_colName NATIONAL VARCHAR(50); DECLARE NO_DATA INT DEFAULT 0; DECLARE cursCol CURSOR FOR SELECT column_name,data_type FROM `columns` -- WHERE table_name = v_tableName; WHERE table_name = 'tbl_users'; DECLARE CONTINUE HANDLER FOR SQLEXCEPTION BEGIN SET NO_DATA = -2; END; DECLARE CONTINUE HANDLER FOR NOT FOUND SET NO_DATA = -1; OPEN cursCol; SET v_string = CONCAT('INSERT ',v_tableName,'('); SET v_stringData = ''; SET NO_DATA = 0; FETCH cursCol INTO v_colName,v_dataType; IF NO_DATA <> 0 then -- NOT SUPPORTED print CONCAT('Table ',@tableName, ' not found, processing skipped.') close cursCol; LEAVE SWL_return; end if; WHILE NO_DATA = 0 DO IF v_dataType in('varchar','char','nchar','nvarchar') then SET v_stringData = CONCAT(v_stringData,'SQLWAYS_EVAL# ll(',v_colName,'SQLWAYS_EVAL# ''+'); ELSE if v_dataType in('text','ntext') then -- SQLWAYS_EVAL# -- SQLWAYS_EVAL# else SET v_stringData = CONCAT(v_stringData,'SQLWAYS_EVAL# ll(cast(',v_colName,'SQLWAYS_EVAL# 00)),'''')+'''''',''+'); ELSE IF v_dataType = 'money' then -- SQLWAYS_EVAL# doesn't get converted -- SQLWAYS_EVAL# implicitly SET v_stringData = CONCAT(v_stringData,'SQLWAYS_EVAL# y,''''''+ isnull(cast(',v_colName,'SQLWAYS_EVAL# 0)),''0.0000'')+''''''),''+'); ELSE IF v_dataType = 'datetime' then SET v_stringData = CONCAT(v_stringData,'SQLWAYS_EVAL# time,''''''+ isnull(cast(',v_colName, 'SQLWAYS_EVAL# 0)),''0'')+''''''),''+'); ELSE IF v_dataType = 'image' then SET v_stringData = CONCAT(v_stringData,'SQLWAYS_EVAL# ll(cast(convert(varbinary,',v_colName, 'SQLWAYS_EVAL# 6)),''0'')+'''''',''+'); ELSE SET v_stringData = CONCAT(v_stringData,'SQLWAYS_EVAL# ll(cast(',v_colName,'SQLWAYS_EVAL# 0)),''0'')+'''''',''+'); end if; end if; end if; end if; end if; SET v_string = CONCAT(v_string,v_colName,','); SET NO_DATA = 0; FETCH cursCol INTO v_colName,v_dataType; END WHILE; END $$ DELIMITER ;

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• gcc optimization? bug? and its practial implication to project

  - by kumar_m_kiran

  Hi All, My questions are divided into three parts Question 1 Consider the below code, #include <iostream> using namespace std; int main( int argc, char *argv[]) { const int v = 50; int i = 0X7FFFFFFF; cout<<(i + v)<<endl; if ( i + v < i ) { cout<<"Number is negative"<<endl; } else { cout<<"Number is positive"<<endl; } return 0; } No specific compiler optimisation options are used or the O's flag is used. It is basic compilation command g++ -o test main.cpp is used to form the executable. The seemingly very simple code, has odd behaviour in SUSE 64 bit OS, gcc version 4.1.2. The expected output is "Number is negative", instead only in SUSE 64 bit OS, the output would be "Number is positive". After some amount of analysis and doing a 'disass' of the code, I find that the compiler optimises in the below format - Since i is same on both sides of comparison, it cannot be changed in the same expression, remove 'i' from the equation. Now, the comparison leads to if ( v < 0 ), where v is a constant positive, So during compilation itself, the else part cout function address is added to the register. No cmp/jmp instructions can be found. I see that the behaviour is only in gcc 4.1.2 SUSE 10. When tried in AIX 5.1/5.3 and HP IA64, the result is as expected. Is the above optimisation valid? Or, is using the overflow mechanism for int not a valid use case? Question 2 Now when I change the conditional statement from if (i + v < i) to if ( (i + v) < i ) even then, the behaviour is same, this atleast I would personally disagree, since additional braces are provided, I expect the compiler to create a temporary built-in type variable and them compare, thus nullify the optimisation. Question 3 Suppose I have a huge code base, an I migrate my compiler version, such bug/optimisation can cause havoc in my system behaviour. Ofcourse from business perspective, it is very ineffective to test all lines of code again just because of compiler upgradation. I think for all practical purpose, these kinds of error are very difficult to catch (during upgradation) and invariably will be leaked to production site. Can anyone suggest any possible way to ensure to ensure that these kind of bug/optimization does not have any impact on my existing system/code base? PS : When the const for v is removed from the code, then optimization is not done by the compiler. I believe, it is perfectly fine to use overflow mechanism to find if the variable is from MAX - 50 value (in my case).

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• why gcc emits segmentation ,after my code run

  - by gcc

  every time ,why have I encountered with segmentation fault ? still,I have not found my fault sometimes, gcc emits segmentation fault ,sometimes, memory satck limit is exceeded I think you will understand (easily) what is for that code void my_main() { char *tutar[50],tempc; int i=0,temp,g=0,a=0,j=0,d=1,current=0,command=0,command2=0; do{ tutar[i]=malloc(sizeof(int)); scanf("%s",tutar[i]); temp=*tutar[i]; } while(temp=='x'); i=0; num_arrays=atoi(tutar[i]); i=1; tempc=*tutar[i]; if(tempc!='x' && tempc!='d' && tempc!='a' && tempc!='j') { current=1; arrays[current]=malloc(sizeof(int)); l_arrays[current]=calloc(1,sizeof(int)); c_arrays[current]=calloc(1,sizeof(int));} i=1; current=1; while(1) { tempc=*tutar[i]; if(tempc=='x') break; if(tempc=='n') { ++current; arrays[current]=malloc(sizeof(int)); l_arrays[current]=calloc(1,sizeof(int)); c_arrays[current]=calloc(1,sizeof(int)); ++i; continue; } if(tempc=='d') { ++i; command=atoi(tutar[i])-1; free(arrays[command]); free(l_arrays[command]); free(c_arrays[command]); ++i; continue; } if(tempc=='j') { ++i; current=atoi(tutar[i])-1; if(arrays[current]==NULL) { arrays[current]=malloc(sizeof(int)); l_arrays[current]=calloc(1,sizeof(int)); c_arrays[current]=calloc(1,sizeof(int)); ++i; } else { a=l_arrays[current]; j=l_arrays[current]; ++i;} continue; } } }

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• casting doubles to integers in order to gain speed

  - by antirez

  Hello all, in Redis (http://code.google.com/p/redis) there are scores associated to elements, in order to take this elements sorted. This scores are doubles, even if many users actually sort by integers (for instance unix times). When the database is saved we need to write this doubles ok disk. This is what is used currently: snprintf((char*)buf+1,sizeof(buf)-1,"%.17g",val); Additionally infinity and not-a-number conditions are checked in order to also represent this in the final database file. Unfortunately converting a double into the string representation is pretty slow. While we have a function in Redis that converts an integer into a string representation in a much faster way. So my idea was to check if a double could be casted into an integer without lost of data, and then using the function to turn the integer into a string if this is true. For this to provide a good speedup of course the test for integer "equivalence" must be fast. So I used a trick that is probably undefined behavior but that worked very well in practice. Something like that: double x = ... some value ... if (x == (double)((long long)x)) use_the_fast_integer_function((long long)x); else use_the_slow_snprintf(x); In my reasoning the double casting above converts the double into a long, and then back into an integer. If the range fits, and there is no decimal part, the number will survive the conversion and will be exactly the same as the initial number. As I wanted to make sure this will not break things in some system, I joined #c on freenode and I got a lot of insults ;) So I'm now trying here. Is there a standard way to do what I'm trying to do without going outside ANSI C? Otherwise, is the above code supposed to work in all the Posix systems that currently Redis targets? That is, archs where Linux / Mac OS X / *BSD / Solaris are running nowaday? What I can add in order to make the code saner is an explicit check for the range of the double before trying the cast at all. Thank you for any help.

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• Are Objective-C initializers allowed to share the same name?

  - by NattKatt

  I'm running into an odd issue in Objective-C when I have two classes using initializers of the same name, but differently-typed arguments. For example, let's say I create classes A and B: A.h: #import <Cocoa/Cocoa.h> @interface A : NSObject { } - (id)initWithNum:(float)theNum; @end A.m: #import "A.h" @implementation A - (id)initWithNum:(float)theNum { self = [super init]; if (self != nil) { NSLog(@"A: %f", theNum); } return self; } @end B.h: #import <Cocoa/Cocoa.h> @interface B : NSObject { } - (id)initWithNum:(int)theNum; @end B.m: #import "B.h" @implementation B - (id)initWithNum:(int)theNum { self = [super init]; if (self != nil) { NSLog(@"B: %d", theNum); } return self; } @end main.m: #import <Foundation/Foundation.h> #import "A.h" #import "B.h" int main (int argc, const char * argv[]) { NSAutoreleasePool * pool = [[NSAutoreleasePool alloc] init]; A *a = [[A alloc] initWithNum:20.0f]; B *b = [[B alloc] initWithNum:10]; [a release]; [b release]; [pool drain]; return 0; } When I run this, I get the following output: 2010-04-26 20:44:06.820 FnTest[14617:a0f] A: 20.000000 2010-04-26 20:44:06.823 FnTest[14617:a0f] B: 1 If I reverse the order of the imports so it imports B.h first, I get: 2010-04-26 20:45:03.034 FnTest[14635:a0f] A: 0.000000 2010-04-26 20:45:03.038 FnTest[14635:a0f] B: 10 For some reason, it seems like it's using the data type defined in whichever @interface gets included first for both classes. I did some stepping through the debugger and found that the isa pointer for both a and b objects ends up the same. I also found out that if I no longer make the alloc and init calls inline, both initializations seem to work properly, e.g.: A *a = [A alloc]; [a initWithNum:20.0f]; If I use this convention when I create both a and b, I get the right output and the isa pointers seem to be different for each object. Am I doing something wrong? I would have thought multiple classes could have the same initializer names, but perhaps that is not the case.

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• Daemonize() issues on Debian

  - by djTeller

  Hi, I'm currently writing a multi-process client and a multi-treaded server for some project i have. The server is a Daemon. In order to accomplish that, i'm using the following daemonize() code: static void daemonize(void) { pid_t pid, sid; /* already a daemon */ if ( getppid() == 1 ) return; /* Fork off the parent process */ pid = fork(); if (pid < 0) { exit(EXIT_FAILURE); } /* If we got a good PID, then we can exit the parent process. */ if (pid > 0) { exit(EXIT_SUCCESS); } /* At this point we are executing as the child process */ /* Change the file mode mask */ umask(0); /* Create a new SID for the child process */ sid = setsid(); if (sid < 0) { exit(EXIT_FAILURE); } /* Change the current working directory. This prevents the current directory from being locked; hence not being able to remove it. */ if ((chdir("/")) < 0) { exit(EXIT_FAILURE); } /* Redirect standard files to /dev/null */ freopen( "/dev/null", "r", stdin); freopen( "/dev/null", "w", stdout); freopen( "/dev/null", "w", stderr); } int main( int argc, char *argv[] ) { daemonize(); /* Now we are a daemon -- do the work for which we were paid */ return 0; } I have a strange side effect when testing the server on Debian (Ubuntu). The accept() function always fail to accept connections, the pid returned is -1 I have no idea what causing this, since in RedHat & CentOS it works well. When i remove the call to daemonize(), everything works well on Debian, when i add it back, same accept() error reproduce. I've been monitring the /proc//fd, everything looks good. Something in the daemonize() and the Debian release just doesn't seem to work. (Debian GNU/Linux 5.0, Linux 2.6.26-2-286 #1 SMP) Any idea what causing this? Thank you

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• Tokenizing a string with variable whitespace

  - by Ron Holcomb

  I've read through a few threads detailing how to tokenize strings, but I'm apparently too thick to adapt their suggestions and solutions into my program. What I'm attempting to do is tokenize each line from a large (5k+) line file into two strings. Here's a sample of the lines: 0 -0.11639404 9.0702948e-05 0.00012207031 0.0001814059 0.051849365 0.00027210884 0.062103271 0.00036281179 0.034423828 0.00045351474 0.035125732 The difference I'm finding between my lines and the other sample input from other threads is that I have a variable amount of whitespace between the parts that I want to tokenize. Anyways, here's my attempt at tokenizing: #include <iostream> #include <iomanip> #include <fstream> #include <string> using namespace std; int main(int argc, char *argv[]) { ifstream input; ofstream output; string temp2; string temp3; input.open(argv[1]); output.open(argv[2]); if (input.is_open()) { while (!input.eof()) { getline(input, temp2, ' '); while (!isspace(temp2[0])) getline(input, temp2, ' '); getline (input, temp3, '\n'); } input.close(); cout << temp2 << endl; cout << temp3 << endl; return 0; } I've clipped it some, since the troublesome bits are here. The issue that I'm having is that temp2 never seems to catch a value. Ideally, it should get populated with the first column of numbers, but it doesn't. Instead, it is blank, and temp3 is populated with the entire line. Unfortunately, in my course we haven't learned about vectors, so I'm not quite sure how to implement them in the other solutions for this I've seen, and I'd like to not just copy-paste code for assignments to get things work without actually understanding it. So, what's the extremely obvious/already been answered/simple solution I'm missing? I'd like to stick to standard libraries that g++ uses if at all possible.

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• Problem in storing the dynamic data in NSMutableArray?

  - by Rajendra Bhole

  I want to develop an application in which firstly i was develop an structure code for storing X and y axis. struct TCo_ordinates { float x; float y; }; . Then in drawRect method i generating an object of structure like. struct TCo_ordinates *tCoordianates; Now I drawing the graph of Y-Axis its code is. fltX1 = 30; fltY1 = 5; fltX2 = fltX1; fltY2 = 270; CGContextMoveToPoint(ctx, fltX1, fltY1); CGContextAddLineToPoint(ctx, fltX2, fltY2); NSArray *hoursInDays = [[NSArray alloc] initWithObjects:@"1",@"2",@"3",@"4",@"5",@"6",@"7",@"8",@"9",@"10",@"11",@"12", nil]; for(int intIndex = 0 ; intIndex < [hoursInDays count] ; fltY2-=20, intIndex++) { CGContextSetRGBStrokeColor(ctx, 2, 2, 2, 1); //CGContextSetRGBStrokeColor(ctx, 1.0f/255.0f, 1.0f/255.0f, 1.0f/255.0f, 1.0f); CGContextMoveToPoint(ctx, fltX1-3 , fltY2-40); CGContextAddLineToPoint(ctx, fltX1+3, fltY2-40); CGContextSelectFont(ctx, "Helvetica", 14.0, kCGEncodingMacRoman); CGContextSetTextDrawingMode(ctx, kCGTextFill); CGContextSetRGBFillColor(ctx, 0, 255, 255, 1); CGAffineTransform xform = CGAffineTransformMake( 1.0, 0.0, 0.0, -1.0, 0.0, 0.0); CGContextSetTextMatrix(ctx, xform); const char *arrayDataForYAxis = [[hoursInDays objectAtIndex:intIndex] UTF8String]; float x1 = fltX1-23; float y1 = fltY2-37; CGContextShowTextAtPoint(ctx, x1, y1, arrayDataForYAxis, strlen(arrayDataForYAxis)); CGContextStrokePath(ctx); Now i want to store generated the values of x1 and y1 in NSMutableArray dynamically, for that i was written the code. NSMutableArray *yAxisCoordinates = [[NSMutableArray alloc] autorelease]; for(int yObject = 0; yObject < intIndex; yObject++) { [yAxisCoordinates insertObject:(tCoordianates->x = x1,tCoordianates->y = y1) atIndex:yObject]; } But it didn't working. How i store the x1 and y1 values in yAxisCoordinates object. The above code is correct?????????????

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• get return value from 2 threads in C

  - by polslinux

  #include <stdio.h> #include <stdlib.h> #include <pthread.h> #include <stdint.h> #include <inttypes.h> typedef struct tmp_num{ int tmp_1; int tmp_2; }t_num; t_num t_nums; void *num_mezzo_1(void *num_orig); void *num_mezzo_2(void *num_orig); int main(int argc, char *argv[]){ pthread_t thread1, thread2; int tmp=0,rc1,rc2,num; num=atoi(argv[1]); if(num <= 3){ printf("Questo è un numero primo: %d\n", num); exit(0); } if( (rc1=pthread_create( &thread1, NULL, &num_mezzo_1, (void *)&num)) ){ printf("Creazione del thread fallita: %d\n", rc1); exit(1); } if( (rc2=pthread_create( &thread2, NULL, &num_mezzo_2, (void *)&num)) ){ printf("Creazione del thread fallita: %d\n", rc2); exit(1); } t_nums.tmp_1 = 0; t_nums.tmp_2 = 0; pthread_join(thread1, (void **)(&t_nums.tmp_1)); pthread_join(thread2, (void **)(&t_nums.tmp_2)); tmp=t_nums.tmp_1+t_nums.tmp_2; printf("%d %d %d\n", tmp, t_nums.tmp_1, t_nums.tmp_2); if(tmp>2){ printf("Questo NON è un numero primo: %d\n", num); } else{ printf("Questo è un numero primo: %d\n", num); } exit(0); } void *num_mezzo_1(void *num_orig){ int cont_1; int *n_orig=(int *)num_orig; t_nums.tmp_1 = 0; for(cont_1=1; cont_1<=(*n_orig/2); cont_1++){ if((*n_orig % cont_1) == 0){ (t_nums.tmp_1)++; } } pthread_exit((void *)(&t_nums.tmp_1)); return NULL; } void *num_mezzo_2(void *num_orig){ int cont_2; int *n_orig=(int *)num_orig; t_nums.tmp_2 = 0; for(cont_2=((*n_orig/2)+1); cont_2<=*n_orig; cont_2++){ if((*n_orig % cont_2) == 0){ (t_nums.tmp_2)++; } } pthread_exit((void *)(&t_nums.tmp_2)); return NULL; } How this program works: i have to input a number and this program will calculate if it is a prime number or not (i know that it is a bad algorithm but i only need to learn pthread). The problem is that the returned values are too much big.For example if i write "12" the value of tmp tmp_1 tmp_2 into the main are 12590412 6295204 6295208.Why i got those numbers??

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• Illegal Instruction When Programming C++ on Linux

  - by remagen

  Heyo, My program, which does exactly the same thing every time it runs (moves a point sprite into the distance) will randomly fail with the text on the terminal 'Illegal Instruction'. My googling has found people encountering this when writing assembly which makes sense because assembly throws those kinds of errors. But why would g++ be generating an illegal instruction like this? It's not like I'm compiling for Windows then running on Linux (which even then, as long as both are on x86 shouldn't AFAIK cause an Illegal Instruction). I'll post the main file below. I can't reliably reproduce the error. Although, if I make random changes (add a space here, change a constant there) that force a recompile I can get a binary which will fail with Illegal Instruction every time it is run, until I try setting a break point, which makes the illegal instruction 'dissapear'. :( #include <stdio.h> #include <stdlib.h> #include <GL/gl.h> #include <GL/glu.h> #include <SDL/SDL.h> #include "Screen.h" //Simple SDL wrapper #include "Textures.h" //Simple OpenGL texture wrapper #include "PointSprites.h" //Simple point sprites wrapper double counter = 0; /* Here goes our drawing code */ int drawGLScene() { /* These are to calculate our fps */ static GLint T0 = 0; static GLint Frames = 0; /* Move Left 1.5 Units And Into The Screen 6.0 */ glLoadIdentity(); glTranslatef(0.0f, 0.0f, -6); glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT | GL_STENCIL_BUFFER_BIT); glEnable(GL_POINT_SPRITE_ARB); glTexEnvi(GL_POINT_SPRITE, GL_COORD_REPLACE, GL_TRUE); glBegin( GL_POINTS ); /* Drawing Using Triangles */ glVertex3d(0.0,0.0, 0); glVertex3d(1.0,0.0, 0); glVertex3d(1.0,1.0, counter); glVertex3d(0.0,1.0, 0); glEnd( ); /* Finished Drawing The Triangle */ /* Move Right 3 Units */ /* Draw it to the screen */ SDL_GL_SwapBuffers( ); /* Gather our frames per second */ Frames++; { GLint t = SDL_GetTicks(); if (t - T0 >= 50) { GLfloat seconds = (t - T0) / 1000.0; GLfloat fps = Frames / seconds; printf("%d frames in %g seconds = %g FPS\n", Frames, seconds, fps); T0 = t; Frames = 0; counter -= .1; } } return 1; } GLuint objectID; int main( int argc, char **argv ) { Screen screen; screen.init(); screen.resize(800,600); LoadBMP("./dist/Debug/GNU-Linux-x86/particle.bmp"); InitPointSprites(); while(true){drawGLScene();} }

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• What is wrong with this C++ Code ?

  - by mr.bio

  Hi .. i am a beginner and i have a problem : this code doesnt compile : main.cpp: #include <stdlib.h> #include "readdir.h" #include "mysql.h" #include "readimage.h" int main(int argc, char** argv) { if (argc>1){ readdir(argv[1]); // test(); return (EXIT_SUCCESS); } std::cout << "Bitte Pfad angeben !" << std::endl ; return (EXIT_FAILURE); } readimage.cpp #include <Magick++.h> #include <iostream> #include <vector> using namespace Magick; using namespace std; void readImage(std::vector<string> &filenames) { for (unsigned int i = 0; i < filenames.size(); ++i) { try { Image img("binary/" + filenames.at(i)); for (unsigned int y = 1; y < img.rows(); y++) { for (unsigned int x = 1; x < img.columns(); x++) { ColorRGB rgb(img.pixelColor(x, y)); // cout << "x: " << x << " y: " << y << " : " << rgb.red() << endl; } } cout << "done " << i << endl; } catch (Magick::Exception & error) { cerr << "Caught Magick++ exception: " << error.what() << endl; } } } readimage.h #ifndef _READIMAGE_H #define _READIMAGE_H #include <Magick++.h> #include <iostream> #include <vector> #include <string> using namespace Magick; using namespace std; void readImage(vector<string> &filenames) #endif /* _READIMAGE_H */ If want to compile it with this code : g++ main.cpp Magick++-config --cflags --cppflags --ldflags --libs readimage.cpp i get this error message : main.cpp:5: error: expected initializer before ‘int’ i have no clue , why ? :( Can somebody help me ? :)

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• if non zero elements in same column count only once

  - by George

  I want to check the elements above the main diagonal and if I found non zero values , count one. If the non zero values are found in the same column ,then count just one ,not the number of the non zero values. For example , it should be count = 2 and not 3 in this example because 12 and 6 are in the same column. A= 1 11 12 4 5 6 0 7 0 #include <stdio.h> #include <stdlib.h> #include <math.h> int main( int argc, const char* argv[] ){ int Rows = 3 , Cols = 3; float *A = (float *) malloc ( Rows * Cols * sizeof (float) ); A[0] = 1.0; A[1] = 11.0; A[2] = 12.0; A[3] = 4.0; A[4] = 5.0; A[5] = 6.0; A[6] = 0.0; A[7] = 7.0; A[8] = 0.0; // print input matrix printf("\n Input matrix \n\n"); for ( int i = 0; i < Rows; i++ ) for ( int j = 0; j < Cols; j++ ) { printf("%f\t",A[ i * Cols + j ]); if( j == Cols-1 ) printf("\n"); } printf("\n"); int count = 0; for ( int j = 0 ; j < Cols; j++ ) { for ( int i = ( Rows - 1 ); i >= 0; i-- ) { // check the diagonal elements above the main diagonal if ( j > i ) { if ( ( A[ i * Cols + j ] != 0 ) ) { printf("\n Above nonzero Elmts = %f\n",( A[i * Cols + j] ) ); count++; } } } } printf("\ncount = %d\n",count ); return 0; }

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• Can't iterate over nestled dict in django

  - by fredrik

  Hi, Im trying to iterate over a nestled dict list. The first level works fine. But the second level is treated like a string not dict. In my template I have this: {% for product in Products %} <li> <p>{{ product }}</p> {% for partType in product.parts %} <p>{{ partType }}</p> {% for part in partType %} <p>{{ part }}</p> {% endfor %} {% endfor %} </li> {% endfor %} It's the {{ part }} that just list 1 char at the time based on partType. And it seams that it's treated like a string. I can however via dot notation reach all dict but not with a for loop. The current output looks like this: Color C o l o r Style S ..... The Products object looks like this in the log: [{'product': <models.Products.Product object at 0x1076ac9d0>, 'parts': {u'Color': {'default': u'Red', 'optional': [u'Red', u'Blue']}, u'Style': {'default': u'Nice', 'optional': [u'Nice']}, u'Size': {'default': u'8', 'optional': [u'8', u'8.5']}}}] What I trying to do is to pair together a dict/list for a product from a number of different SQL queries. The web handler looks like this: typeData = Products.ProductPartTypes.all() productData = Products.Product.all() langCode = 'en' productList = [] for product in productData: typeDict = {} productDict = {} for type in typeData: typeDict[type.typeId] = { 'default' : '', 'optional' : [] } productDict['product'] = product productDict['parts'] = typeDict defaultPartsData = Products.ProductParts.gql('WHERE __key__ IN :key', key = product.defaultParts) optionalPartsData = Products.ProductParts.gql('WHERE __key__ IN :key', key = product.optionalParts) for defaultPart in defaultPartsData: label = Products.ProductPartLabels.gql('WHERE __key__ IN :key AND partLangCode = :langCode', key = defaultPart.partLabelList, langCode = langCode).get() productDict['parts'][defaultPart.type.typeId]['default'] = label.partLangLabel for optionalPart in optionalPartsData: label = Products.ProductPartLabels.gql('WHERE __key__ IN :key AND partLangCode = :langCode', key = optionalPart.partLabelList, langCode = langCode).get() productDict['parts'][optionalPart.type.typeId]['optional'].append(label.partLangLabel) productList.append(productDict) logging.info(productList) templateData = { 'Languages' : Settings.Languges.all().order('langCode'), 'ProductPartTypes' : typeData, 'Products' : productList } I've tried making the dict in a number of different ways. Like first making a list, then a dict, used tulpes anything I could think of. Any help is welcome! Bouns: If someone have an other approach to the SQL quires, that is more then welcome. I feel that it kinda stupid to run that amount of quires. What is happening that each product part has a different label base on langCode. ..fredrik

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• mysql changing delimiter

  - by jimsmith

  I'm trying to add this function using php myadmin, first off I get on error line 5, which is apparently because you need to change the delimiter from ; to something else so i tried this DELIMITER | CREATE FUNCTION LEVENSHTEIN (s1 VARCHAR(255), s2 VARCHAR(255)) RETURNS INT DETERMINISTIC BEGIN DECLARE s1_len, s2_len, i, j, c, c_temp, cost INT; DECLARE s1_char CHAR; DECLARE cv0, cv1 VARBINARY(256); SET s1_len = CHAR_LENGTH(s1), s2_len = CHAR_LENGTH(s2), cv1 = 0x00, j = 1, i = 1, c = 0; IF s1 = s2 THEN RETURN 0; ELSEIF s1_len = 0 THEN RETURN s2_len; ELSEIF s2_len = 0 THEN RETURN s1_len; ELSE WHILE j <= s2_len DO SET cv1 = CONCAT(cv1, UNHEX(HEX(j))), j = j + 1; END WHILE; WHILE i <= s1_len DO SET s1_char = SUBSTRING(s1, i, 1), c = i, cv0 = UNHEX(HEX(i)), j = 1; WHILE j <= s2_len DO SET c = c + 1; IF s1_char = SUBSTRING(s2, j, 1) THEN SET cost = 0; ELSE SET cost = 1; END IF; SET c_temp = CONV(HEX(SUBSTRING(cv1, j, 1)), 16, 10) + cost; IF c > c_temp THEN SET c = c_temp; END IF; SET c_temp = CONV(HEX(SUBSTRING(cv1, j+1, 1)), 16, 10) + 1; IF c > c_temp THEN SET c = c_temp; END IF; SET cv0 = CONCAT(cv0, UNHEX(HEX(c))), j = j + 1; END WHILE; SET cv1 = cv0, i = i + 1; END WHILE; END IF; RETURN c; END DELIMITER ; But I get this error: #1064 - You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'delimiter | Please help !?

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• What can cause System.Move to occasionaly give wrong results?

  - by Fredrik Loftheim

  The last few days we have had some strange problems with our database components developed by a third party. There has been no changes to these components for months. The code that HAS changed the last few days is our own code and we have also updated our gui-components developed by another third party. After debugging I have found that a call to System.Move in one of the database component procedures occationaly gives wrong results! Please take a look at the code below from the database components and read my comments. How can this inconsistent behaviour happen? Can anyone give me an idea of how to procede to find the cause of this inconsistent behaviour? NB! I dont think there is anything wrong with THIS code, it is only shown to explain the problem "symptoms". My guess is that there is some sort of memory corruption or something, caused by our code or the updated gui-component-code. Edit: Take a look at the blogpost linked below. It seems that it could be related to my problem. At least as I read it it confirms that System.Move can give wrong results: http://blog.excastle.com/2007/08/28/delphi-bug-of-the-day-fpu-stack-leak/ Procedure InternalDescribe; var cbufl: sb4; //sb4=LongInt cbuf: array[0..30] of char; cbufp: PChar; //.... begin //..Some code repeat //...Some code to initialize cbufp and cbufl //On the 15. iteration the values immediately Before Move are always these: //cbufp = 'STDPRODUCTSTOREDELEMENTSCOUNT' //cbuf = ('S', 'T', 'A', 'T', 'U', 'S', #0, 'E', 'V', 'A', 'R', 'R', 'E', 'C', 'I', 'D', #0, 'D', 'U', 'C', 'T', 'I', 'D', #0, #0, #0, #0, #0, #0, #0, #0) //cbufl = 29 Move(cbufp^, cbuf, cbufl); //Values immediately After Move should then be: //cbuf = ('S', 'T', 'D', 'P', 'R', 'O', 'D', 'U', 'C', 'T', 'S', 'T', 'O', 'R', 'E', 'D', 'E', 'L', 'E', 'M', 'E', 'N', 'T', 'S', 'C', 'O', 'U', 'N', 'T', #0, #0) //But sometimes this Move results in this value( 1 in 5..15 times): //cbuf = ('S', 'T', 'D', 'P', 'R', 'O', 'D', 'U', 'C', 'T', 'S', 'T', 'O', 'R', 'E', 'D', #0, #0, #0, #0, #0, 'N', 'T', 'S', 'C', 'O', 'U', 'N', 'T', #0, #0) } until SomeCondition; //...Some more code end;

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