10 More Discussions You Might Find Interesting
1. UNIX for Advanced & Expert Users
Hi,
I have a VM with following configration .
3.10.0-693.1.1.el7.x86_64 #1 SMP Thu Aug 3 08:15:31 EDT 2017 x86_64 x86_64 x86_64 GNU/Linux
My current POSIX is :--
Your environment variables take up 2011 bytes
POSIX upper limit on argument length (this system): 2093093
POSIX smallest... (15 Replies)
Discussion started by: Abhayman
15 Replies
2. Programming
I want to create a program that creates 2 child process, and each of them creates 2 threads, and each thread prints its thread id. I0ve allread done that the outuput isn't the outuput i want.
When a run the following comand "$./a.out | sort -u | wc -l" I have the folowing output
2
$:
It should... (3 Replies)
Discussion started by: pharaoh
3 Replies
3. UNIX for Advanced & Expert Users
Hi,
consider the code below:
#include <stdio.h>
.
.
struct myStruct
{
char *message ;
int id;
};
.
.
.
void *thread_function( void *ptr );
nt main()
{
pthread_t thread1, thread2 ,thread3 ;
struct myStruct nico1; (2 Replies)
Discussion started by: Behnaz
2 Replies
4. Programming
HI,
When i am configuring php in SUN Solaris. I am getting the below error.
configure: error: Your system seems to lack POSIX threads.
Do i need to install POSIX? If so can somebody let me know where can i download POSIX for Solaris 8?
Thanks, (2 Replies)
Discussion started by: Krrishv
2 Replies
5. Programming
Hello !
Let's supose I have a main function in C , and two POSIX threads. I give you an example down :
int main() {
int something;
char else;
void *FirstThread();
void *SecondThread();
..
<start those two pthreads ..>
return 0;}
void *FirstThread() { ... }
void *SecondThread()... (2 Replies)
Discussion started by: !_30
2 Replies
6. UNIX for Dummies Questions & Answers
how to read POSIX? poe six or not? (3 Replies)
Discussion started by: robin.zhu
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7. BSD
Hi! Everybody%)
I got a question like this: Does my FreeBSD5.1 support Posix queues.
Thanks! (7 Replies)
Discussion started by: kamazi
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8. UNIX for Advanced & Expert Users
I wanted study and write a unix like system. who can help me.
-------------
Removed the garbled characters... not sure why they were there... (2 Replies)
Discussion started by: crashsky
2 Replies
9. Programming
Please,does anybody can give me any general info about unix(posix) ? (1 Reply)
Discussion started by: Haris Astreos
1 Replies
10. UNIX for Dummies Questions & Answers
What is posix? What is the relation between Posix, Unix and linux? (1 Reply)
Discussion started by: darbarilal
1 Replies
MEMCPY(3) Linux Programmer's Manual MEMCPY(3)
NAME
memcpy - copy memory area
SYNOPSIS
#include <string.h>
void *memcpy(void *dest, const void *src, size_t n);
DESCRIPTION
The memcpy() function copies n bytes from memory area src to memory area dest. The memory areas must not overlap. Use memmove(3) if the
memory areas do overlap.
RETURN VALUE
The memcpy() function returns a pointer to dest.
ATTRIBUTES
For an explanation of the terms used in this section, see attributes(7).
+----------+---------------+---------+
|Interface | Attribute | Value |
+----------+---------------+---------+
|memcpy() | Thread safety | MT-Safe |
+----------+---------------+---------+
CONFORMING TO
POSIX.1-2001, POSIX.1-2008, C89, C99, SVr4, 4.3BSD.
NOTES
Failure to observe the requirement that the memory areas do not overlap has been the source of significant bugs. (POSIX and the C stan-
dards are explicit that employing memcpy() with overlapping areas produces undefined behavior.) Most notably, in glibc 2.13 a performance
optimization of memcpy() on some platforms (including x86-64) included changing the order in which bytes were copied from src to dest.
This change revealed breakages in a number of applications that performed copying with overlapping areas. Under the previous implementa-
tion, the order in which the bytes were copied had fortuitously hidden the bug, which was revealed when the copying order was reversed. In
glibc 2.14, a versioned symbol was added so that old binaries (i.e., those linked against glibc versions earlier than 2.14) employed a mem-
cpy() implementation that safely handles the overlapping buffers case (by providing an "older" memcpy() implementation that was aliased to
memmove(3)).
SEE ALSO
bcopy(3), bstring(3), memccpy(3), memmove(3), mempcpy(3), strcpy(3), strncpy(3), wmemcpy(3)
COLOPHON
This page is part of release 4.15 of the Linux man-pages project. A description of the project, information about reporting bugs, and the
latest version of this page, can be found at https://www.kernel.org/doc/man-pages/.
2017-09-15 MEMCPY(3)