Recent questions tagged C

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I was just reading ISO/IEC 9899:201x Committee Draft - April 12, 2011 in which i found under 5.1.2.2.3 Program ... be 0 but it shows 9 why? 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 the need for fflush() and problems associated with it

Below is sample code for using fflush(): #include <string.h> #include <stdio.h> #include <conio.h> #include < ... there be with using fflush(). 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 - Efficiency of CUDA vector types (float2, float3, float4)

I'm trying to understand the integrate_functor in particles_kernel.cu from CUDA examples: struct integrate_functor ... function make_float4? 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 the source code of memcpy()

00018 void *memcpy(void *dst, const void *src, size_t len) 00019 { 00020 size_t i; 00021 00022 /* 00023 ... ). Why is this calculation required? 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 - GCC linking libc static and some other library dynamically, revisited?

The following questions are relevant but do not answer my question: Linking partially static and partially dynamic in ... in gcc Neither works. 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 - Under what circumstances can malloc return NULL?

It has never happened to me, and I've programming for years now. Can someone give me an example of a non- ... an integer, causes malloc to fail. 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 - pthread_exit vs. return

I have a joinable pthread runner function defined as below: void *sumOfProducts(void *param) { ... pthread_exit ... be preferred over the other? 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 encoding of argv?

It's not clear to me what encodings are used where in C's argv. In particular, I'm interested in ... LC_ALL=my_encoding to change your locale. 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 does the extern keyword mean?

What does the extern keyword mean? I've seen that in front of an function declaration like extern void DoFoo ... 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 obtain, and synchronize, a complete list of all X11 windows?

I want to monitor all the open windows under X11. Currently, I'm doing this as follows: Initially walking the whole tree ... ); } } 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 - how to use void ** pointer correctly?

I am trying to use a double void pointer but I am a little bit confused about the usage. I have a struct ... then could you please correct 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 - why does accessing an element in an array take constant time?

Lets say I have an array as: int a[]={4,5,7,10,2,3,6} when I access an element, such as a[3], ... I would like to learn more from you guys) 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 - Undefined reference to main - collect2: ld returned 1 exit status

I'm trying to compile a program (called es3), but, when I write from terminal: gcc es3.c -o es3 it appears ... 1 exit status What could 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 - What is the difference between casting to `float` and adding `f` as a suffix when initializing a `float`?

What is the difference between float f = (float) 99.32 ; and float f = 99.32f ; Both of them compiled and ran 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 - Count the number of occurrences of 0's in integers from 1 to N

How will you efficiently count number of occurrences of 0's in the decimal representation of integers from 1 to N ... to work for this problem? 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 - Getting smooth, big points in OpenGL

I started playing around with OpenGL and GLUT. I would like to draw some points, but the problem is that they ... , only their shape is 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 - How to find the size of integer array

How to find the size of an integer array in C. Any method available without traversing the whole array once, to find out the size of the array. 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 perf cache events meaning?

I am trying to figure out why a modified C program is running faster than its non modified counter part ( ... 0.002822122 seconds time elapsed 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 I assume the size of long int is always 4 bytes?

Is it always true that long int (which as far as I understand is a synonym for long) is 4 bytes? Can I rely ... be true for a POSIX based OS? 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 types like uint32, int32, uint64, int64 defined in any stdlib header?

I often see source code using types like uint32, uint64 and I wonder if they should be defined by the ... on my application source 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 - Total number of possible triangles from n numbers

If n numbers are given, how would I find the total number of possible triangles? Is there any method that ... conditions for being a triangle. 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 bitmap file into structure

I would like to read a bitmap file into a struct and manipulate it like eg. making a mirror effect, but I ... it. Thank you for your 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 - Null termination of char array

Consider following case: #include<stdio.h> int main() { char A[5]; scanf("%s",A); printf("%s",A); } My ... for '' which sizeof() doesn't count? 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 - Difference between char and int when declaring character

I just started learning C and am rather confused over declaring characters using int and char. I am well ... to declare a character 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 - How can I get GDB to tell me what address caused a segfault?

I'd like to know if my program is accessing NULL pointers or stale memory. The backtrace looks like this: Program ... #1 0x0058e900 in ?? () 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 make an infinite empty loop that won't be optimized away?

The C11 standard appears to imply that iteration statements with constant controlling expressions should not be ... optimizations turned on? 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's the algorithm behind sleep()?

Now there's something I always wondered: how is sleep() implemented ? If it is all about using an API from ... the process in running state" ? 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 preprocessor - How do I make a C++ macro behave like a function?

Let's say that for some reason you need to write a macro: MACRO(X,Y). (Let's assume there's a good reason ... get more votes than my method. :) See Question&Answers more detail:os...

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

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