Recent questions tagged C

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Simple question, When i use fread: fread(ArrayA, sizeof(Reg), sizeBlock, fp); My file pointer, fp is moved ahead? 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 - Type punning with void * without breaking the strict aliasing rule in C99

I recently came across the strict aliasing rule, but I'm having trouble understanding how to use void * to perform ... of the void * in C99? 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 I check my byte flag, verifying that a specific bit is at 1 or 0?

I use a byte to store some flag like 10101010, and I would like to know how to verify that a specific bit is at 1 or 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 - how is select() alerted to an fd becoming "ready"?

I don't know why I'm having a hard time finding this, but I'm looking at some linux code where we' ... such that the select() statement returns? 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 difference between a static global and a static volatile variable?

I have used a static global variable and a static volatile variable in file scope, both are updated by an ... appreciable. 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 can I kill a pthread that is in an infinite loop, from outside that loop?

I create a thread and I put it into an infinite loop. I get memory leaks when checking the code with valgrind. ... th) but I still get leaks. 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 - list_entry in Linux

user/include/linux/list.h this declaration: #define list_entry(ptr, type, member) ((type *)((char *)(ptr) - ... little bit stuck with this one. 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 - If a global variable is initialized to 0, will it go to BSS?

All the initialized global/static variables will go to initialized data section. All the uninitialized global/static ... will be stored? 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 - Assembly x86 - "leave" Instruction

It's said that the "leave" instruction is similar to: movl %ebp, %esp popl %ebp I understand the movl %ebp, ... purpose of the popl %ebp 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 - Fix for dereferencing type-punned pointer will break strict-aliasing

I'm trying to fix two warnings when compiling a specific program using GCC. The warnings are: warning: ... suitable union for this case? 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 it better to allocate memory in the power of two?

When we use malloc() to allocate memory, should we give the size which is in power of two? Or we just ... now? Kindly explain it. 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 - Properly using sscanf

I am supposed to get an input line that can be in of any of the following formats: There must be space between ... to work. I use strict C89. 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 - fflush() is not working in Linux

I used the fflush() in Linux GCC but it did not work. Are there any alternatives for that function? Here ... ? Is there an alternative function? 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 - Set IP address using SIOCSIFADDR ioctl

I am trying to get and set the IP address using the IOCTL interface on Linux. I am successfully able to get ... , SIOCSIFADDR, (char *)&ifr); 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 typedef a storage-class-specifier?

I tried the following code #include <stdio.h> int main(void) { typedef static int sint; sint i = 10; return 0; ... ? or Where am I going wrong?! 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 - Members of Dirent structure

I have started working with dirent.h library and I came across a very useful member of "struct dirent" structer ... are they used for? Regards 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 - Expression must be a modifiable L-value

I have here char text[60]; Then I do in an if: if(number == 2) text = "awesome"; else text = " ... said expression must be a modifiable L-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 - How do I find the next multiple of 10 of any integer?

Dynamic integer will be any number from 0 to 150. i.e. - number returns 41, need to return 50. If number is ... way to achieve this? 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 - Jump to Bootloader in STM32 through application i.e using Boot 0 and Boot 1 Pins in Boot mode from User flash

I have a requirement for firmware upgrade. I am planning to use USB DFU class. But command for firmware upgrade ... we jump to System Memory? 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 exactly does fopen(), fclose() work?

I was just wondering about the functions fopen, fclose, socket and closesocket. When calling fopen or opening a ... and sending the data. 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 difference between - 1) Preprocessor,linker, 2)Header file,library? Is my understanding correct?

Okay, until this morning I was thoroughly confused between these terms. I guess I have got the difference, ... in binary unreadable form? 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 interface with the Linux tun driver

I'm having a hard time figuring this problem out - I am trying to write a program that will interact ... greatly appreciated. Thanks; ~Robert 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 are those strange array sizes [*] and [static] in C99?

Apparently the following function prototypes are valid in C99 and C11: void foo(int a[const *]); void bar( ... are they just syntactic sugar? 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 - Latest changes in C11

C1x has become ISO/IEC 9899:2011 aka C11. Does anyone know what changes (if any) there are in the ... the DC minutes should cover things. 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 - Mutex lock threads

Am new to multi threaded/processs programming. So here's what I need to clarify. Process A code ... mutexes, threads and processes? 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 - Const vs Static Const

How does the compiler (e.g. GCC) allocates const and static const variable, as in, where would it reside? In data memory or program memory? 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 - Understanding set/getsockopt SO_SNDBUF size doubles

Hi I have the following program to check the send buffer size for a UDP socket. However, I the return value ... or how to interpret the output? 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 - dereferencing pointer to incomplete type

I've seen a lot of questions on this but I'm going to ask the question differently without specific code. Is ... , which isn't very helpful. See Question&Answers more detail:os...

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

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