Search Results

Search found 7500 results on 300 pages for 'const char'.

Page 84/300 | < Previous Page | 80 81 82 83 84 85 86 87 88 89 90 91  | Next Page >

• shared library in C

  - by sasayins

  Hi, I am creating a shared library in C but don't know what is the correct implementation of the source codes. I want to create an API like for example, printHello, int printHello( char * text ); This printHello function will call another function: In source file, libprinthello.c, void printHello( char * text ) { printHi(); printf("%s", text); } Since this printHello function is the interface for the user or application: In header file libprinthello.h, extern void printHello( char * text); Then in the source file of the printHi function, printhi.c void printHi() { printf("Hi\n"); } Then my problem is, since printHello is the only function that I want to expose in the user, what implementation should I do in printHi function?

  Read the article

• "Undefined Symbols" when inheriting from stdexcept classes

  - by Austin Hyde

  Here is an exception defined in <stdexcept>: class length_error : public logic_error { public: explicit length_error(const string& __arg); }; Here is my exception: class rpn_expression_error : public logic_error { public: explicit rpn_expression_error(const string& __arg); }; Why do I get this error when <stdexcept> does not? Undefined symbols: rpn_expression_error::rpn_expression_error(/*string*/ const&), referenced from: ... ld: symbol(s) not found

  Read the article

• Accessing structure elements using pointers

  - by Arun Nadesh

  Hi Everybody, Greetings! I got surprised when the following program did not crash. typedef struct _x{ int a; char b; int c; }x; main() { x *ptr=0; char *d=&ptr->b; } As per my understanding the -> operator has higher precedence over & operator. So I expected the program to crash at the below statement when we try to dereference the NULL pointer tr. char *d=&ptr->b; But the statement &ptr->b evaluates to a valid address. Could somebody please explain where I'm wrong? Thanks & Regards, Arun

  Read the article

• Hex to Decimal conversion in C

  - by darkie15

  Hi All, Here is my code which is doing the conversion from hex to decimal. The hex values are stored in a unsigned char array: int liIndex ; long hexToDec ; unsigned char length[4]; for (liIndex = 0; liIndex < 4 ; liIndex++) { length[liIndex]= (unsigned char) *content; printf("\n Hex value is %.2x", length[liIndex]); content++; } hexToDec = strtol(length, NULL, 16); Each array element contains 1 byte of information and I have read 4 bytes. When I execute it, here is the output that I get : Hex value is 00 Hex value is 00 Hex value is 00 Hex value is 01 Chunk length is 0 Can any one please help me understand the error here. Th decimal value should have come out as 1 instead of 0. Regards, darkie

  Read the article

• How to pass the structure to a function in C++ defined in another class?

  - by Dany

  I have a class Con as this:- class Con { public: struct MachineList { BSTR AccountId; BSTR MachineId; BSTR Make; char* Make1; BSTR Model; char* Model1; BSTR SerialNumber; BSTR IpAddress; char* IpAddress1; BSTR Port; int Port1; BSTR LocationCode; } machinelist[100] ; int w; } ; i created an object of Con class as Con m_con; I have another class Test class Test { public: void fun();//i want to pass the object of the structure that i created in Con //what arguments should i pass in fun function? };

  Read the article

• Using an array in embedded x86 assembly??

  - by Mark V.

  Hey all I have a method (C++) that returns a character and takes an array of characters as its parameters. I'm messing with assembly for the first time and just trying to return the first character of the array in the dl register. Here's what I have so far: char returnFirstChar(char arrayOfLetters[]) { char max; __asm { push eax push ebx push ecx push edx mov dl, 0 mov eax, arrayOfLetters[0] xor edx, edx mov dl, al mov max, dl pop edx pop ecx pop ebx pop eax } return max; } For some reason this method returns a ? Any idea whats going on? Thanks

  Read the article

• Embedding binary blobs using gcc mingw

  - by myforwik

  I am trying to embed binary blobs into an exe file. I am using mingw gcc. I make the object file like this: ld -r -b binary -o binary.o input.txt I then look objdump output to get the symbols: objdump -x binary.o And it gives symbols named: _binary_input_txt_start _binary_input_txt_end _binary_input_txt_size I then try and access them in my C program: #include <stdlib.h> #include <stdio.h> extern char _binary_input_txt_start[]; int main (int argc, char *argv[]) { char *p; p = _binary_input_txt_start; return 0; } Then I compile like this: gcc -o test.exe test.c binary.o But I always get: undefined reference to _binary_input_txt_start Does anyone know what I am doing wrong?

  Read the article

• Converting from ANSI to Unicode

  - by Rayne

  Hi all, I'm using Visual Studio .NET 2003, and I'm trying to convert a program written in purely ANSI characters to be independent of Unicode/Multi-byte characters. The program has a callback function of pcap_loop, called "got_packet". It's defined as void got_packet(u_char *user, const struct pcap_pkthdr *header, const u_char *cpacket) { USES_CONVERSION; _TUCHAR *packet; packet = A2T(cpacket); ... } However, I get the error message error C2440: 'type cast': cannot convert from 'const u_char *' to 'ATL::CA2WEX<>' How do fix this? Thank you. Regards, Rayne

  Read the article

• Why is this default template parameter not allowed?

  - by Matt Joiner

  I have the following class: template <typename Type = void> class AlignedMemory { public: AlignedMemory(size_t alignment, size_t size) : memptr_(0) { int iret(posix_memalign((void **)&memptr_, alignment, size)); if (iret) throw system_error("posix_memalign"); } virtual ~AlignedMemory() { free(memptr_); } operator Type *() const { return memptr_; } Type *operator->() const { return memptr_; } //operator Type &() { return *memptr_; } //Type &operator[](size_t index) const; private: Type *memptr_; }; And attempt to instantiate an automatic variable like this: AlignedMemory blah(512, 512); This gives the following error: src/cpfs/entry.cpp:438: error: missing template arguments before ‘buf’ What am I doing wrong? Is void not an allowed default parameter?

  Read the article

• C++ 'mutable' keyword

  - by Rob

  A while ago I came across some code that marked a member variable of a class with the 'mutable' keyword. As far as I can see it simply allows you to modify a variable in a 'const' method: class Foo { private: mutable bool done_; public: void doSomething() const { ...; done_ = true; } }; Is this the only use of this keyword or is there more to it than meets the eye? I have since used this technique in a class, marking a boost::mutex as mutable allowing const functions to lock it for thread-safety reasons, but, to be honest, it feels like a bit of a hack.

  Read the article

• anagram!! problem with this code

  - by danielDhobbs

  hello people!! i have a problem with this code can you fix it for me? int anagram(char* word, int cur, int len){ int i, b = cur+1; char temp=0; char arrA[len]; printf("//%d**%d//", b, cur); for (i = 0 ; i < len ; i++) { arrA[i] = word[i]; } for (i = cur ; i < len ; i++) { if (b < len) { printf("%s\n", arrA); temp = arrA[cur]; arrA[cur] = arrA[b]; arrA[b] = temp; b++; } else if (b == len) anagram(arrA, b, len); } return 0; }

  Read the article

• Does printf have side effects?

  - by martani_net

  I have an array of the following strcuture struct T_info { char capitale[255]; char pays[255]; char commentaire[255]; }; struct T_info *tableau; Then when I populate the array and call printf allone on each element it works fine strcpy(tab[line].capitale, buffer); strcpy(tab[line].pays, buffer); strcpy(tab[line].commentaire, buffer); printf("%s\n", tab[line].capitale); printf("%s\n", tab[line].pays); printf("%s\n", tab[line].commentaire); but if I call, printf("%s, %s, %s", tab[line].capitale, tab[line].pays, tab[line].commentaires) I get wrong resutts, is printf changing its parameters or what is going on?

  Read the article

• Variadic functions and arguments assignment in C/C++

  - by Rizo

  I was wondering if in C/C++ language it is possible to pass arguments to function in key-value form. For example in python you can do: def some_function(arg0 = "default_value", arg1): # (...) value1 = "passed_value" some_function(arg1 = value1) So the alternative code in C could look like this: void some_function(char *arg0 = "default_value", char *arg1) { ; } int main() { char *value1 = "passed_value"; some_function(arg1 = value1); return(0); } So the arguments to use in some_function would be: arg0 = "default_value" arg1 = "passed_value" Any ideas?

  Read the article

• inserting std::strings in to a std::map

  - by PaulH

  I have a program that reads data from a file line-by-line. I would like to copy some substring of that line in to a map as below: std::map< DWORD, std::string > my_map; DWORD index; // populated with some data char buffer[ 1024 ]; // populated with some data char* element_begin; // points to some location in buffer char* element_end; // points to some location in buffer > element_begin my_map.insert( std::make_pair( index, std::string( element_begin, element_end ) ) ); This std::map<>::insert() operation takes a long time (It doubles the file parsing time). Is there a way to make this a less expensive operation? Thanks, PaulH

  Read the article

• realloc()ing memory for a buffer used in recv()

  - by Hristo

  I need to recv() data from a socket and store it into a buffer, but I need to make sure get all of the data so I have things in a loop. So to makes sure I don't run out of room in my buffer, I'm trying to use realloc to resize the memory allocated to the buffer. So far I have: // receive response int i = 0; int amntRecvd = 0; char *pageContentBuffer = (char*) malloc(4096 * sizeof(char)); while ((amntRecvd = recv(proxySocketFD, pageContentBuffer + i, 4096, 0)) > 0) { i += amntRecvd; realloc(pageContentBuffer, 4096 + sizeof(pageContentBuffer)); } However, this doesn't seem to be working properly since Valgrind is complaining "valgrind: the 'impossible' happened:". Any advice as to how this should be done properly? Thanks, Hristo

  Read the article

• Why isn't wchar_t widely used in code for Linux / related platforms?

  - by Ninefingers

  This intrigues me, so I'm going to ask - for what reason is wchar_t not used so widely on Linux/Linux-like systems as it is on Windows? Specifically, the Windows API uses wchar_t internally whereas I believe Linux does not and this is reflected in a number of open source packages using char types. My understanding is that given a character c which requires multiple bytes to represent it, then in a char[] form c is split over several parts of char* whereas it forms a single unit in wchar_t[]. Is it not easier, then, to use wchar_t always? Have I missed a technical reason that negates this difference? Or is it just an adoption problem?

  Read the article

• C++ overloading operator comma for variadic arguments

  - by uray

  is it possible to construct variadic arguments for function by overloading operator comma of the argument? i want to see an example how to do so.., maybe something like this: template <typename T> class ArgList { public: ArgList(const T& a); ArgList<T>& operator,(const T& a,const T& b); } //declaration void myFunction(ArgList<int> list); //in use: myFunction(1,2,3,4); //or maybe: myFunction(ArgList<int>(1),2,3,4);

  Read the article

• How to convert a unicode charactor array back to unicode sequence in C++

  - by eddyxd

  My problem is how to convert a c/c++ string/chractor array to another string contain the unicode(UTF-16) escape sequence of original one for example, I want to find a function F(char *ch) could do following function. char a[10] = "\u5f53"; printf("a = %s\n",a); char b[10]; b = F(a); //<- F is the function I wanted printf("b = %s\n",b); -------- console will show ------- a = ? b = \u5f53 Anyone has any Idea@@?~ thanks!! ps: I tried to guess \u5f35 means the value store in a, but it is not indeed the value of a[0] = -79 , a[1] = 105 ... So I don't know how to convert it back to the sequence of unicode.... Please give me a hane~ : )

  Read the article

• A question for retrieve minix os version

  - by majnun

  Hi guys i'm having a project for the university in which (above others ) i have to get the minix os version from kernell call.I'm not a very experienced programmer so this is what i have come to (with some help ) int main (int argc, char *argv[] ) { char M3ca1[23]; message ml; m.m_u.m_m1.m3ca1= OS_VERSION; char temp=_syscall(MM,69,&m); printf("the os version is %c\n",temp); return 0; } and i get multiple errors.IF you have any ideas it would be greatly appreciated.

  Read the article

• Function Pointer from base class

  - by camelord

  Hi there, i need a Function Pointer from a base class. Here is the code: class CActionObjectBase { ... void AddResultStateErrorMessage( const char* pcMessage , ULONG iResultStateCode); ... } CActionObjectCalibration( ): CActionObjectBase() { ... m_Calibration = new CCalibration(&CActionObjectBase::AddResultStateErrorMessage); } class CCalibration { ... CCalibration(void (CActionObjectBase::* AddErrorMessage)(const char*, ULONG )); ... void (CActionObjectBase::* m_AddErrorMessage)(const char*, ULONG ); } Inside CCalibration in a Function occurs the Error. I try to call the Function Pointer like this: if(m_AddErrorMessage) { ... m_AddErrorMessage("bla bla", RSC_FILE_ERROR); } The Problem is, that I cannot compile. The Error Message says something like: error C2064: Expression is no Function, that takes two Arguments. What is wrong? regards camelord

  Read the article

• Copy constructor demo (crashing... case 2)

  - by AKN

  Please have a glance at this program: class CopyCon { public: char *name; CopyCon() { name = new char[20]; name = "Hai";//_tcscpy(name,"Hai"); } CopyCon(const CopyCon &objCopyCon) { name = new char[_tcslen(objCopyCon.name)+1]; _tcscpy(name,objCopyCon.name); } ~CopyCon() { if( name != NULL ) { delete[] name; name = NULL; } } }; int main() { CopyCon obj1; CopyCon obj2(obj1); cout<<obj1.name<<endl; cout<<obj2.name<<endl; } This program crashes on execution. Error: "Expression: _BLOCK_TYPE_IS_VALID(pHead-nBlockUse)" If I assign "Hai" to name using aasignment operator, its crashing. Where as when I use string func _tcscpy to assign "Hai" to name, its working perfectly. Can some one explain why so?

  Read the article

• DB2 ZOS String Comparison Problem

  - by John

  I am comparing some CHAR data in a where clause in my sql like this, where PRI_CODE < PriCode The problem I am having is when the CHAR values are of different lengths. So if PRI_CODE = '0800' and PriCode = '20' it is returning true instead of false. It looks like it is comparing it like this '08' < '20' instead of like '0800' < '20' Does a CHAR comparison start from the Left until one or the other values end? If so how do I fix this? My values can have letters in it so convering to numeric is not an option.

  Read the article

• how to read character from console in c++?

  - by tsubasa

  I'm struggling with reading characters from console in c++. Here is what I tried to do: char x; char y; char z; cout<<"Please enter your string: "; string s; getline(cin,s); istringstream is(s); is>> x >> y >> z; The problem is if the user enter something like this "1 20 100": x will get 1 y will get 2 z will get 0 What I want to get is x = 1; y = 20; z = 100; Anybody has suggestions?

  Read the article

• Why does this code read all ' ' for the anything after the 4th character?

  - by djs22

  #define fileSize 100000 int main(int argc, char *argv[]){ char *name=argv[1]; char ret[fileSize]; FILE *fl = fopen(name, "rb"); fseek(fl, 0, SEEK_END); long len = fileSize; fseek(fl, 0, SEEK_SET); //fread(ret, 1, len, fl); int i; *(ret+fileSize) = '\0'; for (i=0; i<fileSize; i++){ *(ret+i)=fgetc(fl); printf("byte : %s \n", ret); } fclose(fl); } In the above code, when I feed the name of a jpeg file, it reads anything after the 4th character as ' '...any ideas? Thanks!

  Read the article

• Trying to understand strtok

  - by Karthick

  Consider the following snippet that uses strtok to split the string madddy. char* str = (char*) malloc(sizeof("Madddy")); strcpy(str,"Madddy"); char* tmp = strtok(str,"d"); std::cout<<tmp; do { std::cout<<tmp; tmp=strtok(NULL, "dddy"); }while(tmp!=NULL); It works fine, the output is Ma. But by modifying the strtok to the following, tmp=strtok(NULL, "ay"); The output becomes Madd. So how does strtok exactly work? I have this question because I expected strtok to take each and every character that is in the delimiter string to be taken as a delimiter. But in certain cases it is doing that way but in few cases, it is giving unexpected results. Could anyone help me understand this?

  Read the article

< Previous Page | 80 81 82 83 84 85 86 87 88 89 90 91  | Next Page >