Recent questions tagged C

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How do I get the HTTP status code (eg 200 or 500) after calling curl_easy_perform? See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - How to render text in SDL2?

I'm using an SDL_Window and SDL_Renderer. Is it possible to use SDL_TTF with SDL_Render/SDL_Window? If so, how? See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - Getting IPV4 address from a sockaddr structure

How can I extract an IP address into a string? I can't find a reference that tells me how char sa_data[14] is encoded. See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - kill a process started with popen

After opening a pipe to a process with popen, is there a way to kill the process that has been started? (Using ... but I need to kill it.) See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - memory allocation in Stack and Heap

This may seem like a very basic question, but its been in my head so: When we allocate a local variable, it ... Same question for heap as well. See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - System call vs Function call

What is the difference between a system call and a function call? Is fopen() a system call or a function call? See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - Sockets - How to find out what port and address I'm assigned

I'm having trouble figuring this out - I'm working with sockets in C using this guide - http://binarii.com/ ... and Port I'm actually assigned? See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - Can a pointer ever point to itself?

My question is: If a pointer variable has the same address as its value, is it really pointing to itself? ... a self pointing pointer useful? See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - When is pthread_spin_lock the right thing to use (over e.g. a pthread mutex)?

Given that pthread_spin_lock is available, when would I use it, and when should one not use them ? i.e. how ... mutex or a pthread spinlock ? See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - What are the differences between a compiler and a linker?

What is the difference between a compiler and a linker in C? See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - How can I get what my main function has returned?

In a C program if we want to give some input from terminal then we can give it by: int main(int argc, ... ) returns a value greater than 125? See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - Variable declaration after goto Label

Today I found one interesting thing. I didn't know that one can't declare a variable after a goto label. ... why am I getting this error? See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - 3d Accelerometer calculate the orientation

I have accelerometer values for the 3 axes (usually when there is only gravity contains data between -1.0 and 1.0 ): ... (Ry/R, Rz/R)*180/M_PI; See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - Is my spin lock implementation correct and optimal?

I'm using a spin lock to protect a very small critical section. Contention happens very rarely so a spin lock ... lock once every few days. See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - "strlen(s1) - strlen(s2)" is never less than zero

I am currently writing a C program that requires frequent comparisons of string lengths so I wrote the ... explain this strange behavior? See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - What's the point of LEA EAX, [EAX]?

LEA EAX, [EAX] I encountered this instruction in a binary compiled with the Microsoft C compiler. It clearly can't ... . Then why is it there? See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - Delete a file named "NUL" on Windows

I ran a program on Windows 7 that was compiled under Cygwin and passed "NUL" as an output file name. Instead ... program under Cygwin to do it? See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - What is the function of an asterisk before a function name?

I've been confused with what I see on most C programs that has unfamiliar function declaration for me. void * ... what this * asterisk implies. See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - How to use PTRACE to get a consistent view of multiple threads?

While I was working on this question, I've come across a possible idea that uses ptrace, but I'm ... references would be greatly appreciated! See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - Function to Calculate a CRC16 Checksum

I'm working on a library to provide simple reliable communication over an RS232 or RS485 connection. Part of this ... I might be going wrong? See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - Does malloc() allocate a contiguous block of memory?

I have a piece of code written by a very old school programmer :-) . it goes something like this ... out any loopholes with this approach See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - How to modify memory contents using GDB?

I know that we can use several commands to access and read memory: for example, print, p, x... But how ... location (while debugging in GDB)? See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - How to increase performance of memcpy

Summary: memcpy seems unable to transfer over 2GB/sec on my system in a real or test application. What can I do ... post your time as a comment? See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - Why use asprintf() instead of sprintf()?

I'm having a hard time understanding why you would need asprintf. Here in the manual it says The functions asprintf ... saying char* = (string) See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - Getting started with autotools

Anyone recommend how a person could get started with autotools in building a C project? See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - Global variables in header file

I have a 2 modules (.c files) and one .h header file: file1.c: #include <stdio.h> #include "global.h" ... works fine. What is going on? See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - Can multithreading be implemented on a single processor system?

I have always followed the concept that multithreading can only be implemented on multiple processors system ... multiple processor systems? See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - dup2 / dup - why would I need to duplicate a file descriptor?

I'm trying to understand the use of dup2 and dup. From the man page : DESCRIPTION dup and dup2 create a copy ... dup2 / dup is needed. Thanks See Question&Answers more detail:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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