Recent questions tagged c

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c - MD5 hash calculates differently on server

I am running some code that I have written in C which calls the md5 hashing functionality from a hashing library that ... when debugging....... See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - stealing bits from a pointer

In The Art of Multiprocessor Programming, p215, the authors say that in C, you could "steal" a bit from a ... so an example would help me. See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - int to char casting

int i = 259; /* 03010000 in Little Endian ; 00000103 in Big Endian */ char c = (char)i; /* returns 03 ... the byte pointed by the i variable. See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - find smallest area that contains all the rectangles

This is an interview question. We are given dimensions of various rectangles, we have to find out the area(minimum ... for max length ,width? See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - Compare int and unsigned int

If one needs to compare int x with unsigned int y which is safer/better/nicer in C99 and with gcc 4.4+: (unsigned ... == (int)y Does it matter? See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - Is there any limit on stack memory?

I was going through one of the threads. A program crashed because it had declared an array of 10^6 locally ... . Or am I missing something? See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - Debugging ncurses application with gdb

I'm trying to debug my ncurses application, using gdb. I use tty command to redirect program's I/O ... handle input from redirected terminal? See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - How can barriers be destroyable as soon as pthread_barrier_wait returns?

This question is based on: When is it safe to destroy a pthread barrier? and the recent glibc bug ... having adjusted the semaphore value. See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - read and write to same socket (TCP) using select

We're writing a client and a server to do (what I thought was) pretty simple network communications. Mulitple ... t hog cpu resources } ) See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - Do I have to call memset after I allocated new memory using malloc

#include "stdlib.h" #include "stdio.h" #include "string.h" int main(int argc, char* argv[]) { int *test = malloc ... ,0,sizeof(int) * 15); ? See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - ioctl is not called if cmd = 2

I am developing a kernel module that uses unlocked_ioctl. I tested it with kernel version 2.6.24-23-generic and ... wrong? Thank you in advance, See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - printf() prints string without newline to stdout in line buffer mode after scanf()

I am aware that most terminals are by default in line buffer mode. i.e. output is buffered and not directed to ... . Why is that so? Thanks. See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - Using the open() system call

I'm writing a program that writes output to a file. If this file doesn't exist, I want to create ... necessary permissions when needed? Thanks! See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - Function fread not terminating string by

New to files in C, trying to read a file via fread Here's the content of the file: line1 how Code used ... the string or am I missing something? See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - What is the need of hh and h format specifiers?

In the code below mac_str is char pointer and mac is a uint8_t array: sscanf(mac_str,"%x:%x:%x:%x:%x:%x", ... of using hhx instead of just x? See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - How to enforce the struct bit order with the GCC compiler?

I was wondering if there is a GCC C Compiler directive that allows me to determine the bit order for ... in the manufacturer supplied file. See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - Displaying wide chars with printf

I'm trying to understand how does printf work with wide characters (wchar_t). I've made the following code samples ... problem? How should I do? See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - How to chain BCryptEncrypt and BCryptDecrypt calls using AES in GCM mode?

Using the Windows CNG API, I am able to encrypt and decrypt individual blocks of data with ... or BCryptDecrypt functions successfully? See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - fseek on a position beyond EOF does not trigger EOF using feof, how come?

I'm reading data from a file to memory that is opened with: FILE *f = fopen(path, "rb"); Before I start ... value of fgetc to check for EOF. See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - How to read unicode (utf-8) / binary file line by line

Hi programmers, I want read line by line a Unicode (UTF-8) text file created by Notepad, i don't want display the ... (i m not sure) Thank You. See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - Switching off optimization for a specific function in gcc 4.2.2

Is it possible to switch off optimization of a specific function? A friend of mine has the problem that the gcc ... not have. thanks in advance See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - How to write data to a graphics card without using BIOS?

I want to make an (extremely simple) operating system. I am currently learning about graphics cards. This is what I ... Edit: I am using x86. See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - how to write an integer to a file (the difference between fprintf and fwrite)

I've been trying to write an integer to a file (open mode is w). fprintf wrote it correctly but fwrite ... be a difference in my implementation? See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - Are flexible array members really necessary?

A struct with a flexible array member, apparently, is not intended to be declared, but rather used in conjunction with ... (sizeof(int) * 5); See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - epoll_wait: maxevents

int epoll_wait(int epfd, struct epoll_event *events, int maxevents, int timeout); I'm a little confused about the ... be lower for some reason? See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - libxml2 error with namespaces and xpath

I am pasting some code here that compiles with no warning using gcc file.c -lxml2, assuming that libxml2 is ... time. Could you please help? See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - Lightweight GNU readline alternative

I am looking for a GNU readline alternative. It comes with a lot of features but only couple of them are ... a good option available on linux? See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - Testing Code for Embedded Application

Background: I am developing a largish project using at Atmel AVR atmega2560. This project contains a lot of ... highly appreciated. --Steve See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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