Recent questions tagged C

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I'm learning how to write programs in C using the k&r book (The C Programming Language) and I have a problem with one of ... ]); s[j] = ''; } 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 link OpenSSL with emscripten?

I'm trying to compile some C code that uses OpenSSL with emscripten, but I get unresolved symbol warnings like: ... buffer); 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 - Convert two ASCII Hexadecimal Characters (Two ASCII bytes) in one byte

I want to convert two ASCII bytes to one hexadecimal byte. eg. 0x30 0x43 => 0x0C , 0x34 0x46 => 0x4F ... The ... . Have you got an idea ? 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 - How to redirect RUNTIME ERRORS to STDERR?

I have a C program that uses PIPES to communicate with an external application. I use EXECL for this: execl ... appreciated ;-) Thanks Lynton 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 - Raw socket with device bind using setsockopt() system is not working in Fedora core 6(2.6.18-1.2798.fc6)

Please any one could help on this issue. Please In the below sample code,we had bind raw sock with eth0. but while ... ");} } close(sock); } 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 free() remove the data stored in the dynamically allocated memory?

I wrote a simple program to test the contents of a dynamically allocated memory after free() as below. (I know ... also depend on the compiler? 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 valgrind report my memory as "definitely lost"?

Consider this code: #include <stdlib.h> int* alloc() { return malloc(250 * sizeof(int)); } int main( ... ://stackoverflow.com/a/3857638/578749 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 - python ctypes and sysctl

I have following code import sys from ctypes import * from ctypes.util import find_library libc = cdll.LoadLibrary ... what exactly went 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 - getchar() and reading line by line

For one of my exercises, we're required to read line by line and outputting using ONLY getchar and printf. I'm following ... ", c); } 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 - character array to floating point conversion

I am trying to convert the output buffer(character array) of the code below to floating point format for further ... Response = +1.29273072E-04 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 - Extracting client certificate & private key from .p12 file

Can anybody tell me how to use PKCS12 *d2i_PKCS12_fp(FILE *fp, PKCS12 **p12); int PKCS12_parse(PKCS12 ... reference will also work. 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 - warning: implicit declaration of function ‘getresuid’ (and ‘seteuid’)

I would like to get rid of the warnings. When I compile the source code with gcc -Wall -ansi -o test test.c I get ... (Red Hat 4.4.7-3) (GCC) 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 - Size of struct containing double field

Firstly, I understand byte padding in structs. But I have still a small test contain a double field in struct and I ... it for me, 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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676 views

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c - Locking Linux Serial Port

I have an issue that I'm trying to solve regarding the serial port in Linux. I'm able to open, read from, ... to it. Thanks for the 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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646 views

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c - pthread_mutex_lock locks, but no owner is set

I've been working on this one for a few days - As a background, I'm working on taking a single-threaded ... are idle at this time. Cheers See Question&Answers more detail:os...

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

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568 views

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c - Parallelization of a prefix sum (Openmp)

I have two vectors, a[n] and b[n], where n is a large number. a[0] = b[0]; for (i = 1 ... there any approach in openmp for solving 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 - cuda - Zero-copy memory, memory-mapped file

I am trying to create a mapped memory file, containing uint32_ts, and then use that as zero-copy pinned memory as ... exit(EXIT_FAILURE); } } 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 - fork/chroot equivalent for Windows server application

I have written a small custom web server application in C running on Linux. When the application receives a ... so the simpler the better. 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 line by line from a socket buffer

I want to write a function that read line by line from a socket buffer obtained from third parameter from read() ... and how can I 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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870 views

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c - Using GDB with OpenMP

Using GDB I can't seem to print the value of shared variables within OpenMP threads. For example, using the ... + flag. 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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554 views

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c - Why does printf specifier format %n not work?

This is my code: #include <stdio.h> int main(void) { int n; fprintf(stdout, "Hello%n World ", &n); ... -rev0, Built by MinGW-W64 project) See Question&Answers more detail:os...

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

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867 views

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c - Safety of using pthreads in Gtk+2.0 application

I have a simple multithreaded Gtk+2.0 application that acquires data from multiple sources (microphone, webcam, temperature ... 2.0? 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 - Linux Serial Port: Blocking Read with Timeout

I have studied many useful threads and some tutorials, but I'm still having some issues with something that should ... in advance for the 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 - Why doesn't the compiler detect and produce errors when attempting to modify char * string literals?

Assume the following two pieces of code: char *c = "hello world"; c[1] = 'y'; The one above doesn' ... Is there some particular reason for 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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700 views

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c - How to determine the length of an array at compile time?

Are there macros or builtins that can return the length of arrays at compile time in GCC? For example: int ... but cannot find it anymore. See Question&Answers more detail:os...

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

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887 views

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c - Why subtract null pointer in offsetof()?

Linux's stddef.h defines offsetof() as: #define offsetof(TYPE, MEMBER) ((size_t) &((TYPE *)0)->MEMBER ... that would actually make a difference? 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 - CreateProcess method ends up with an error

I've a problem with my following code: int main(int argc, char **argv) { PROCESS_INFORMATION pi; STARTUPINFO si; ... ." What does it means??? See Question&Answers more detail:os...

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

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832 views

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c - Async signal safety of fork()

According to Oracle's Multithreaded Programming Guide, fork() should be safe-to-use inside signal handlers. But my ... be? 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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