C++ :: G++ 4.7.2 Error - Mutex In Namespace STD Does Not Name A Type
Mar 11, 2013I've verified this on ubuntu 12.10 and on windows/mingw, and found that g++ version 4.7.2 seems to have broken thread/mutex support.
View 11 RepliesI've verified this on ubuntu 12.10 and on windows/mingw, and found that g++ version 4.7.2 seems to have broken thread/mutex support.
View 11 RepliesI want to know how mutex is working in process synchronization. Where these mutexes are stored in memory how another process know about this mutex?
If two different mutexes are having same name what will happen?
If any exception occurs in critical section code then what sort of issue which we see in terms of synchronization objects?
Before and after the critical section code, Mutex is locked and unlocked. But if any exception occurs then the waiting thread will be waiting for resource to be freed as Mutex is not unlocked due to the exception.
I was trying to put mutex lock on shared memory but my code is not working. What I want is that if some process is putting something on shared memory segment, other process should not be able to access that segment. For testing , I create a server program which put data in shared memory and client program which access the data.
To test it, I put break point after:
pthread_mutex_lock(&(init_lock));
But I see that client program was able to access shared memory.
Below is code:
Server: Code: pthread_mutex_t init_lock = PTHREAD_MUTEX_INITIALIZER;
main()
{
char c;
[Code].....
Consider how to implement a mutex lock using an atomic hardware instruction. Assume that the following structure defining the mutex lock is available:
Code:
typedef struct {
int available;
}
lock; (available == 0)
indicates that the lock is available, and a value of 1 indicates that the lock is unavailable. Using this struct, illustrate how the following functions can be implemented using the test and set() and compare and swap() instructions:
void acquire(lock *mutex)
void release(lock *mutex)
Be sure to include any initialization that may be necessary.
Q. Consider the following C declaration.
int x[10], y,z;
What kind of error does following statement contain?
z == x +y;
a. Syntax error
b. Semantic error
c. logical error
d. All of the above
According to me it should be option a, but I am confused, how to get confirm answer with explanation.
I have a Polymorphic class and some child classes, of which I need to make multiple instances of, using a list container. I've set the key type to be a unique pointer of the polymorphic class, and the values of each element pointing to a New Child instance, like so:
std::list<std::unique_ptr<Polymorphic>> polymorphic;
polymorphic.push_back(new Child(foo, bar));
The only problem is that when I try to push_back a new element, I get a compiler error, saying "No instance of overloaded function".Should I try and create a pointer object on it's own and push back that object as an element, it will work fine:
std::unique_ptr<Polymorphic> polym(new Child(foo, bar));
std::list<std::unique_ptr<Polymorphic>> polymorphic;
polymorphic.push_back(polym);
Is there some way I can push a new Child instead of having to create a Polymorphic pointer object and pushing that?
I am getting the error on the implementation of my class name. The error is coming from my parkingControl.cpp 'ParkingControl parkingControlMenu;'. I have used this implementation fine before, but once I added a new main it stopped working. Below is my code.
parkingControl.h
#ifndef PARKINGCONTROL_H_INCLUDED
#define PARKINGCONTROL_H_INCLUDED
#include <iostream>
[Code]....
I have two classes declared as below
#include<iostream>
using namespace std;
Class Node
{
[Code].....
I am trying to write a program that reads in an XML file, parses it and prints out information about each tag. I am getting the following errors when trying to build the program:
Parser.cpp:24:1: error: 'Parser' does not name a type
Parser::getXMLData() {
^
Parser.cpp:120:1: error: 'Parser' does not name a type
Parser:rocessXMLData(
[Code] ....
Here is my code for the 5 files.
[ATTACH]main.cpp
[/ATTACH][ATTACH]Parser.h
[/ATTACH][ATTACH]Parser.cpp
[/ATTACH][ATTACH]Element.h
[/ATTACH][ATTACH]Element.cpp[/ATTACH]
When declare and assign an instance of a user-defined struct in a function. And the struct (theStruct) is not declared in the same header file as the function (theFunction). Like this:
files:
"A.h": declares the struct in a class (theClass)
"A.cpp": implements the struct
"B.h": declares the function
"B.cpp": implements the function, error here
I think making the instance (inst) a reference might solve this. But the instance is assigned to a return value from a function (returnFunc). Like:
void theFunction() {
...
theClass::theStruct inst = returnFunc(...);
//returnFunc() returns an instance of theStruct
//the error is at 'inst'
...
}
What do you think?
I have attached the source code I am writing. I have been getting the two following errors. I know it's something to do with the pointer casting.
udp-server.c:174:3: error: subscripted value is neither array nor pointer nor vector
udp-server.c:165:3: error: cannot convert to a pointer type
The file is attached here.
udp-server-edit.txt (7.64K)
Number of downloads: 19
I'm trying to learn recursion, and I'm using a simple array to experiment with it, but I have a couple of annoying errors that I don't understand why they're there. Here's the code:
Code:
#include <cstdlib>
#include <iostream>
using namespace std;
int largest(const int arr[], int lowerIndex, int upperIndex) {
int max;
[code]....
Now try to print the array backwards:
//Use a recursive algorithm to find the largest element in arr:
int largest(arr[], lowerIndex, upperIndex);//error: expected an expression
return 0;
}
I program unix sokcet programming , and part of my code is ti open file from server and open it , but i surprised with this wierd error i dont have any reason for it ?
Code:
#include <errno.h>
#include <stdio.h>
#include <sys/types.h>
#include <sys/socket.h>
[Code] ....
File name is : myHeader.h
myHeader.h:24:1: error: unknown type name "File"???
I've been writing the math functions for a 3d game and tried compiling it at about 30 functions in. I get this error related to my pointers to my structures. it affects almost everything in all my functions (as youll see by looking at how i do the math in the function below). The compiler gives me the error
"error: dereferencing pointer to incomplete type"
on all my struct Type4D pointers but referencing the values in my struct TypeMatrix4X4 using pointers seems to work fine i think (it doesn't seem to complian explicitly about it. so here is the important code...
one example function
Code:
struct Type4D *MatVecMult4X4RtoL(struct TypeMatrix4X4 *mat, struct Type4D *vec) {
struct Type4D *dest = (struct Type4D *) malloc(sizeof(struct Type4D));
[Code]....
I am adding int type into vector called "vi" several times like this.
std::vector<int> vi;
void addFunc(int *a, int cnt) {
vi.erase(vi.begin(), vi.end());
vi.clear();
for(int i=0; i<cnt; i++)
vi.push_back(a[i]);
}
and I call the addfunc N times every sec.
And sometimes it has runtime error on vi.push_back line.
(called stack says "_CrtIsValidHeapPointer")
I am having trouble with this program I get the error dereferencing pointer to incomplete type in the populate function I am using BloodShed's Dev C++ compiler v4.9.9.2 I copied this program out of a book because I was having a problem with a linked list in a similar program. I think there is a problem with the compiler not supporting these types of pointer's in a function.
#include <stdio.h>
struct tel_typ {
char name[25];
char phone_no[15];
struct tel_typ *nextaddr;
[code].....
Is the bool keyword in C exactly like the boolean keyword in Java? why this code is getting an 'unknown type error' when I initiialze looping.
#include <stdio.h>
#include <stdlib.h>
int main()
[Code].....
If I am completely using the boolean concept wrong in C, should I just use break statements instead?
I am getting this error:
drivers/media/video/mxc/capture/gt2005.c:2256:62: error: dereferencing pointer to incomplete type
I am at a loss trying to figure this out. Here it is:
case Sensor_Flash:
{
struct i2c_client *client = to_i2c_client(to_soc_camera_control(icd));
struct sensor *sensor = to_sensor(client);
if (sensor->sensor_io_request && sensor->sensor_io_request->sensor_ioctrl) {
sensor->sensor_io_request->sensor_ioctrl(icd->pdev,Cam_Flash, on);
if(on){
Lines 6 and 7 are giving me the same error. What am I doing wrong?
Below is my code snippet.I'm getting "Error:initialization from incompatible pointer type" error on line 'int *q = status;'.
Obviously, I'm missing something but has no clue...:(
void findwalls(int *p,int y,int x){
int status[y_count][x_count][4];
int *q = status;
for(int i = 0;i < (y_count * x_count * 4);i++)
*(q + i) = *(p + i);
Code:
do {
printf("Edit the entry's cellphone number:");
scanf("%s", addressbook[4][num]);
length = strlen(addressbook[4][num]); //gets the length of the input (should be 10)
//checks if the input is composed of 11 elements wherein the first 2 are 0 and 9 respectively
for(i=0; i<11; i++){
[Code] ....
why do I get an error here?
Code:
if ((addressbook[4][num][0] == '0') && (addressbook[4][num][1] == '9') || (addressbook[4][num][i]>='0') && (addressbook[4][num][i]<='9') && (length=='11'))
And how do I fix this?
The error message is: comparison is always false due to limited data type
I have part of a class that checks to make sure there is a fault that lasts for 60 seconds. The code below is written several times throughout the class for different subsystems dealing with overcurrent.
// Over Current
if (UUV->getCTaps(MOTORCURRPOS_1) > 1.4*UUV->getcurrMode.getMotor().Peak) // The fault {
if (motor1Timer == NULL)
motor1Timer = time(&timer);
else if ( time(&timer) - motor1Timer >= 60)
motor1Over = true;
} else
motor1Timer = NULL;
The timing statement is okay because it works on all of the other fault checkers. It is the if statement that is causing the error I just do not know why.
I am trying to use the Singleton design patterno on Linux, but it is not working:
in the .h I have:
Code:
public:
static ErrorH& Instance();
private:
ErrorH() {};
In the .cpp I have:
Code:
ErrorH& ErrorH::Instance() {
static ErrorH& self = ErrorH();
return self;
}
The errors I get are:
Code:
g++ --g -c ErrorH.cpp -o ErrorH.o
ErrorH.cpp: In static member function "static ErrorH& ErrorH::Instance()":
ErrorH.cpp:9: error: invalid initialization of non-const reference of type "ErrorH&" from a temporary of type "ErrorH"
make: *** [ErrorH.o] Error 1
This code works on Windows, how can I get it to work on Linux?
I am writing a simple program to suck in a txt file then pump it into sql.
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using System.IO;
using System.Data.OleDb;
using System.Data.SqlClient;
[Code] ......
How I can get past this error and get the data into sql? I read a couple articles on .tag but not sure I understand what to do.
I made a simple binary tree then decide to try out threads too. I got the following error:
call of an object of a class type without appropriate operator or conversion
Code:
#include "Tree.h"
#include <iostream>
#include <thread>
void main(void){
[Code] ....
I am having a hard time figuring out why the error exists. I tried adding the new operator but that did not work.
I have a basic vector/point class where I've overloaded a bunch of arithmetical operators:
Code:
#pragma once
class point {
public:
point() {
}
point(float p_x, float p_y, float p_z) : x(p_x), y(p_y), z(p_z)
[Code] ...
I can use it fine like
Code:
point p(50,50,50);
point q(50,50,50);
point t = p * q + q;
However when I put this point type into a struct and try to access the members after passing it through by const reference:
Code:
struct sextic {
point a,b,c,d,e,f,g;
};
inline static sextic sexticDifference(const sextic &p_sextic1, c
[Code] ....
This gives me an "operator not defined" error for compilation.