Recent questions tagged c

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c - Is printf()'s string width safe with unterminated strings?

Is the following well defined? const char not_a_c_string[] = { 'h', 'e', 'l', 'l', 'o' }; printf( " ... where the "%.*s" construct is suggested. 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 - mmap SIGBUS error and initializing the file

I'm trying to model a basic CPU by mmapping a 1 MiB file, corresponding to the RAM size. I want to read/write this ... 1; printf("%i", ram[2]); 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 - Can you use restrict-ed pointers to access the same object in some cases?

Most definitions of restrict say that it's a promise from the programmer to the compiler that for the ... result in undefined behaviour? 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 ignore whitespaces in fscanf()

I need to use fscanf to ignore all the white spaces and to not keep it. I tried to use something like the ... as fgets() but didnt keep it! 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 - Finding the maximum element of an array recursively

Consider this code, which computes the maximum element of an array. #include <stdio.h> int maximum(int arr[], ... block called four (4) times? 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 - Problem with strtok and segmentation fault

I have two helper functions to break up strings in the format of decimal prices ie. "23.00", "2.30" Consider ... 0; else return atoi(tok); } 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 - chdir() not affecting environment variable PWD

When I use chdir() to change the current working directory, why doesn't the getenv("PWD") give the present working ... is "/home/user" "/boot" 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 accept socket with timeout

Is there is a timeout crossplatform soulution to accept client using accept function without setting socket to non- ... fix that? 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 - malloc() in Linux - "there is no guarantee that the memory really is available"?

I'm making a game where the world is divided into chunks of data describing the world. I keep the ... has allocated the requested amount? 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 a gcc flag to catch integer truncation?

Is there a gcc flag to signal a warning/error when I try to put a double value into an int variable? I ... even though I'm losing information. 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 - Why the environment variable is unset after using setenv( )

I wrote a C program in Linux to set the values of environment variables using setenv, but after execution, when I ... "setenv failed on ENV1"); 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 - Why is MAP_GROWSDOWN mapping does not grow?

I tried to create MAP_GROWSDOWN mapping with the expectation it would grow automatically. As specified in the manual ... mean by growing here? 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 - Can an integer be shared between threads safely?

Is there a problem with multiple threads using the same integer memory location between pthreads in a C program ... atomic of operations, right? 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 - Redefining enum enumerators with #define

I have spotted something in C header files what I can't figure out what is for. For example in file bits/ ... google nor this site search box. 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 get attributes from a node in libxml2

I am working on a parser to get data from an XML file. I am using libxml2 to extract data. I am a not ... to get the count of the attributes. 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 - TEMP_FAILURE_RETRY and __USE_GNU

I'm on Ubuntu 10.04 using GCC and I want to use the macro TEMP_FAILURE_RETRY as described here: http://www ... same #ifdef __USE_GNU in my code? 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 - Problem with string conversion to number ( strtod )

I am using strtod( ) function to extract an environment variable as a string, and then changing it to double ... great help. 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 - _Bool type and strict aliasing

I was trying to write some macros for type safe use of _Bool and then stress test my code. For evil testing ... does not mention _Bool at all. 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 - Why printk doesn't print message in kernel log(dmesg)

I wrote small kernel module code as mentioned below, I am testing it in ubuntu 14.04 #include <linux/module.h ... module removed [ 4073.324994] 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 - Why does redefining a static global variable give a compile-time error when redefining a global variable does not?

Compiling code 1 gives an error 'i redefined', but code 2 shows no similar error. Why is it so? Code 1 static int ... . int main(){ return 0; } 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 - Malloc -> how much memory has been allocated?

# include <stdio.h> # include <stdbool.h> # include <string.h> # include <stdlib.h> int main () { ... how much memory is allocated to buffer? 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 - Specific functions vs many Arguments vs context dependent

An Example Suppose we have a text to write and could be converted to "uppercase or lowercase", and can be ... realize of why OOP was invented. 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 - Array of arrays, with different sizes

I'm having an array, that has arrays in every cell. For example, the big array is called arr: int a[3] = {3 ... self. So what can I do? 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 - can we use poll function with unnamed pipes?

I am trying to write a program where i need to monitor ends of unnamed pipe for certain events. ... poll function with functional descriptors 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 - Does socket become unusable after connect() fails?

In Chapter 4, paragraph 4.3 of Steven's "The Socket: Networking API, Third Edition", the author states the ... flow resumed on the same socket. 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 sorting algorithm does qsort use?

I can't find any information regarding what sorting algorithm C qsort function uses. Is it quicksort? It is not mentioned in man. 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 - Naming a variable `current` in a kernel module leads to "function declaration isn’t a prototype" error

I'm learning to write kernel modules for linux as a beginner. What I'm trying to do is to write every task ... Anyone knows how to fix this ?? 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 - Accuracy of floating point arithmetic

I'm having trouble understanding the output of this program int main() { double x = 1.8939201459282359e-308; double y = ... from x + 2.0*y? See Question&Answers more detail:os...

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

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