Recent questions tagged C

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c - Writing to a closed, local TCP socket not failing

I seem to be having a problem with my sockets. Below, you will see some code which forks a server and a client. ... ); } } return 0; } 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 exit a child process - _exit() vs. exit

Consider this code snippet: pid_t cpid = fork(); if (cpid == -1) { perror("fork"); exit(EXIT_FAILURE); } if ( ... Shall I use exit() or _exit()? 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 - Anonymous functions using GCC statement expressions

This question isn't terribly specific; it's really for my own C enrichment and I hope others can find it ... this screw up static analyzers? 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 difference between using _exit() & exit() in a conventional Linux fork-exec?

I've been trying to figure out how the fork-exec mechanism is used inside Linux. Everything was going on ... .. Thanks for any clarification. 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 are malloc() and printf() said as non-reentrant?

In UNIX systems we know malloc() is a non-reentrant function (system call). Why is that? Similarly ... prevents them being guaranteed reentrant? 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 - Returning function pointer type

Often I find the need to write functions which return function pointers. Whenever I do, the basic format I use ... seem redundant in the code. 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 - segfault only when NOT using debugger

I have a multithreaded C program, which consistently generates a segmentation fault at a specific point in the program ... to find the problem! 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 - Check glibc version for a particular gcc compiler

I have two gcc compilers installed on my system, one is gcc 4.1.2 (default) and the other is gcc 4.4.4. ... 2, since it is the default compiler. 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 - atol() v/s. strtol()

What is the difference between atol() & strtol()? According to their man pages, they seem to have the same ... , which function should I use? 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 - Want to compile native Android binary I can run in terminal on the phone

I've been trying for a couple days to compile a native ARM Android binary that will execute on my phone using a ... to the libc on the phone. 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 determine if memory is aligned?

I am new to optimizing code with SSE/SSE2 instructions and until now I have not gotten very far. To my knowledge ... ). Thank you in advance... 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 - Mmap() an entire large file

I am trying to "mmap" a binary file (~ 8Gb) using the following code (test.c). #include <stdio.h> #include ... . What is wrong with my code? 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 - fcntl, lockf, which is better to use for file locking?

Looking for information regarding the advantages and disadvantages of both fcntl and lockf for file locking. ... enforcing mutual exclusion. 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 - Literal string initializer for a character array

In the following rules for the case when array decays to pointer: An lvalue [see question 2.5] of type array ... "? Some example please. 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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c preprocessor - C/C++ macro/template blackmagic to generate unique name

Macros are fine. Templates are fine. Pretty much whatever it works is fine. The example is OpenGL; but the ... at end of block? 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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c - How to append strings using sprintf?

I am facing a serious issue with sprintf. Suppose my code snippet is: sprintf(Buffer,"Hello World"); sprintf(Buffer ... to see all the lines. 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 - faster alternative to memcpy?

I have a function that is doing memcpy, but it's taking up an enormous amount of cycles. Is there a faster ... to move a piece of memory? 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 - Given an audio stream, find when a door slams (sound pressure level calculation?)

Not unlike a clap detector ("Clap on! clap clap Clap off! clap clap Clap on, clap off, the Clapper! clap ... CFAR certainly fits the bill. -Adam 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 format specifier for unsigned short int?

I have the following program #include <stdio.h> int main(void) { unsigned short int length = 10; printf(" ... it was still giving the warning. 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 prefer start + (end - start) / 2 over (start + end) / 2 when calculating the middle of an array?

I've seen programmers use the formula mid = start + (end - start) / 2 instead of using the simpler formula mid ... do they use the former one? 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 - Difference between r+ and w+ in fopen()

In fopen("myfile", "r+") what is the difference between the "r+" and "w+" open mode? I read this: "r" ... "w+", the file will be erased first? 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 - GDB: Listing all mapped memory regions for a crashed process

I've got a full-heap core dump from a dead process on an x86 Linux machine (kernel 2.6.35-22 if it matters) ... proc seem to do what I need. 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 make backtrace()/backtrace_symbols() print the function names?

The Linux specific backtrace() and backtrace_symbols() allows you to produce a call trace of the program. However, it ... foo(); return 0; } 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 solve "ptrace operation not permitted" when trying to attach GDB to a process?

I'm trying to attach a program with gdb but it returns: Attaching to process 29139 Could not attach to process. ... I attach it to debuggers? 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 won't extern link to a static variable?

Why does extern int n not compile when n is declared (in a different file) static int n, but works when ... what about extern am I missing? 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 - Correctness of Sakamoto's algorithm to find the day of week

I am using Sakamoto's algorithm to find out the day of week from a given date. Can anybody tell me the correctness of this ... m-1] + d) % 7; } 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 - Where can one find the C89/C90 standards in PDF format?

I'm looking for a free copy version of the C89/C90 standard, but I can't find it anywhere! Why is so ... helped either, nor did Open Standards. 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 poll and select?

I am referring to the POSIX standard select and poll system C API calls. See Question&Answers more detail:os...

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

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