Recent questions tagged C

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c - What are the differences comparing PIE, PIC code and executable on 64-bit x86 platform?

The test is on Ubuntu 12.04 64-bit. x86 architecture. I am confused about the concept Position Independent ... explain the finding C.. 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 free memory obtained by sbrk()?

I have a custom allocator function which uses sbrk() to obtain memory. How do I release this memory when it's ... the end of the data segment ? 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 valid to use bit fields with union?

I have used bit field with a structure like this, struct { unsigned int is_static: 1; unsigned int is_extern: 1 ... to use bit field with union? 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 - Fast Hypotenuse Algorithm for Embedded Processor?

Is there a clever/efficient algorithm for determining the hypotenuse of an angle (i.e. sqrt(a2 + b2 ... processor without hardware multiply? 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 - Creating big file on Windows

I need to create big relatively big (1-8 GB) files. What is the fastest way to do so on Windows using C or ... and it's taking too long. 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 - printf option

When you are printing a tab character to the standard output using printf in C, it outputs some space ... help or suggestion is appreciated. 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 - The usage of an ampersand(&) in printf and format specifiers

#include <stdio.h> #include <stdlib.h> int main() { char a; printf("What? "); scanf("%s", &a); printf(" ... and this is my first time 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 - In multi thread application how can I redirect stderr & stdout in separate file as per thread?

I have multi thread application in which I'm creating a thread like this: int main(int argc,char *argv ... threads data on different terminals. 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 perform a circular rotation of a byte?

I'm trying to implement a function that performs a circular rotation of a byte to the left and to the right. I wrote the ... &(~(1 << n)); } 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 notifications for SD card events?

I want to check the presence of an SD card, and receive notifications for SD card add/remove. So far I have used ... And I can't use libusb :). See Question&Answers more detail:...

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

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c - C89, Mixing Variable Declarations and Code

I'm very curious to know why exactly C89 compilers will dump on you when you try to mix variable declarations and ... am I totally wrong there? 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: Operation not permitted

I am trying to use mmap in user space to read the physical memory where 'mem_map' starts. It's an array that ... I can get around 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 - Virtual Memory size on Linux

I'm trying to understand in depth the virtual memory management on OS Linux. I don't really understand how the ... : ulimit -v : unlimited 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 a char array be used with any data type?

The malloc() function returns a pointer of type void*. It allocates memory in bytes according to the size_t value ... [128]; return 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 - How to combine shared libraries?

I've got some .so libraries that I'd like to combine into one shared library so that it doesn't depend on the ... I do this? Can I do 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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650 views

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c - Is it possible to create a Minimal Perfect Hash function without a separate lookup table for a small (<64) set of keys?

I recently read this article Throw away the keys: Easy, Minimal Perfect Hashing about generating a minimal perfect hash ... f(thread_ids[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 - memset an array to 1

I am trying to initialize a 2d array with some integer.If I initialize the array to 0 I am getting correct results but ... ---- Not set to 1 } 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 a correct fail-safe process-shared barrier be implemented on Linux?

In a past question, I asked about implementing pthread barriers without destruction races: How can barriers be destroyable ... to resume 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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687 views

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c - Qsort Comparison Function

I am a beginner to C and I am trying to understand the comparison function needed for the qsort function. Part One: ... , and why some don't! 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 the strict aliasing rule really a "two-way street"?

In these comments user @Deduplicator insists that the strict aliasing rule permits access through an incompatible type if ... . (emphasis mine) 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 - zlib, deflate: How much memory to allocate?

I am using zlib to compress a stream of text data. The text data comes in chunks, and for each chunk, ... few kilobytes for small objects. */ 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 - valgrind mac os mem leak

Today I installed valgrind on my Mac os x 10.6 and tried to test it out. And it turned out to be weird ... 0 contexts (suppressed: 0 from 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 can you find the processor number a thread is running on?

I have a memory heap manager which partitions the heap into different segments based on the number of processors on ... on a POSIX system? See Question&Answers more detail:os...

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

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741 views

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c - Can uint8_t be a non-character type?

In this answer and the attached comments, Pavel Minaev makes the following argument that, in C, the only types to ... want to do such a thing. See Question&Answers more detail:os...

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

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625 views

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c - How to copy a string using a pointer

Here's a program I wrote to copy a string constant. When the program is run it crashes. Why is this happening ? ... ; printf("%s ",l); } 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 - __udivdi3 undefined — how to find the code that uses it?

Compiling a kernel module on 32-Bit Linux kernel results in "__udivdi3" [mymodule.ko] undefined! "__umoddi3" ... not check every line manually. 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 - libc random number generator flawed?

Consider an algorithm to test the probability that a certain number is picked from a set of N unique ... The distribution: The differences: 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 - Confusion in data types in a 2D array

Here is a code which print the address of the first element of an 2D array followed by an addition of 1. ... ] 3214383040 &array[0]+1 3214383052 See Question&Answers more detail:os...

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

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