Programming :: Pthread - Take String From The Command Line And Creates A Thread To Print The String
May 3, 2011
I've been trying to understand pthread in C a little better. So I made a simple program that takes in a string from the command line and creates a thread to print the string. I've looked online and copied the basic concepts but there are something things I'm confused about. The programs works just fine, but I have questions. Here's what I have so far.
[Code]....
One thing I'd like to know is why the 3rd argument in the pthread_create function which is my SendMessage function needs to be typecasted to a void pointer and then send the address of the function. Also as for the 4th argument, I would see typecasting to void pointer in some of the pthread examples I saw online, but in my case I'm passing a char pointer, would this be correct? In which case would I ever want to pass a void pointer?
Do I need a pthread_exit(NULL) in my main and in the SendMessage function? If so, why? I added the sleep() function so that I could let the pthread_exit function in my SendMessage function execute first. I simply saw that the online examples on pthread had pthread_exit() in both locations.
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Feb 25, 2011
I need to creates string suffixes out of a Reference string. for eg. suffixes of abcdefg will be
1)bcdefg
2)cdefg
3)defg
and so on...
create an array of pointers to point to the first few characters and then use that pointer to print the rest of the string.But when i print using the pointer i get GARBAGE values! shudn't std::cout<<ptr[w] print the string following the char it is pointing to? why do i get garbage values?
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Oct 16, 2010
I have a set of lines as ahown below:
Leon went to school
Leon came back from school..
Leon had dinner...
I have to replace the line containing "dinner" by a single string LUNCH...
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Mar 7, 2010
i use this script to get the time and date of back and fourth transactions for a particular execution id. I use a substr command on the 5th column to to cut the milli seconds off the time value. - otherwise the times would look like 08:30:04.235
grep <executionID> <auditfile> | awk '{ print $1, $2, $3, $4, substr($5,1,8}
FIX -> Mon 3/1/2010 08:30:04
FIX <- Mon 3/1/2010 08:32:36
FIX <- Mon 3/1/2010 08:35:08
[code].....
anyhow - i append two sed commands to further clarify the direction of the message.
awk '{ print $1, $2, $3, $4, substr($5,1,8} | sed -e 's/->/ ->IN/g' | sed -e 's/<-/<-OUT/g'
FIX -> IN Mon 3/1/2010 08:30:04
FIX <- OUT Mon 3/1/2010 08:32:36
[code]....
I tried using an awk gsub () command within the string instead of the two seds, but it did not work:
awk '{ print gsub(/<regex>/, <replace with>,$1), $2, $3, $4, substr($5,1,8}
the sed works ok, but it would be cooler to make the replacement within the awk command:
gsub(/->/,-> IN, $1)
Is there a way where i could replace the value of the $1 column in the awk print string?
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Oct 22, 2010
copy string a to string b and change string b with toupper() and count the chars
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Mar 13, 2010
I need to search a string which is in the first line and print that column.
For e.g
Code:
$ top -bn1 | head -20 | awk '/PID/,/*/'
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND 13737 admin 15 0 2476 936 680 R 2 0.0 0:00.01
[Code]....
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Apr 18, 2010
So if I'm given a location of a file like:
How can I just take the type of the file at the end? I know I can use strrchr() for a period to get the pointer to the period just before file type. Is there a build in string function that will just take the rest of the string from a certain point on forward in the string? I know it wouldn't be much work to make it myself, but I figured I would find out if it already existed before doing it.
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Mar 13, 2010
Code:
The error is:
Code:
What I want to do is take input of ip4 as a string, convert it to an integer to add 1 to it, then reconvert it back to a string. Its not working.
My full code is:
Code:
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Oct 12, 2009
I've been given a custom-made string class which handles string, wstring and bstr. It has a number of methods and assignment operators to convert to and from different types. The app I work on compiles happily in VS6 and VS2008, but when trying to compile in Redhat (version 4.1.1 in Redhat 5.0)
[code]....
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Nov 11, 2010
I have the following two type of strings1: A/D2: A/C/DI am trying to write a subroutine to check whether all of the letters in string 1 appears in string 2. If yes, return true. If not, return false. In the above example, all the letters (A and D) in string 1 are also present in string 2, so I return true.
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Aug 3, 2010
I need to output of a script to a file with tags.
I'm trying sed and was able to put a tag on the end of the line
Code:
Output is
Quote:
What I need to have is
Quote:
I'm thinking of I redirect my first sed command to a file and then use sed again to put <group> at the beginning of the line. My problem is how to put <group> to all beginning of the string.
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Jul 10, 2010
I want to know the Perl command to replace a string by pointing the line number. I know how to replace a string without pointing a line number but I am in need to replace only the two matching string in a file
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Apr 9, 2010
I have a requirement like this..this just a sample script...
Code:
when i run this scipt...
Code:
Code:
It is appended in the same line...
I want it to be added to the next line.....
I want to do this by explitly using the filehandles in perl....and not with redirection operators in shell.
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Jun 8, 2010
I want to append a variable string to the end of a specific line. not like append the same string to each line. like in my file i have 4 columns, i want to add a string in 5th column in some fixed row.
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Jan 26, 2010
Quote:Originally Posted by topcatI would like to know how i can write a shell script to delete a line if a particular pattern exists?E.g. I have a text file with multiple lines. Say 1000s. in the following pattern.
username@email.com:149.0.3.4:1
username1@email.com:149.0.3.4:1
username1@email.net:149.0.3.4:1
username1@email.edu:149.0.3.4:1
If the patternusername@email.com exists then the line "username@email.com:149.0.3.4:1 should be deleted from the file.I have a very similar question but I need to delete one line in a file which matches one very precise instance of a string only. Let's assume I have a file composed of thousands of lines and let's call the file chap-secrets. Let's take the following sample entries:
Code:
#USERNAME SERVER PASSWORD IP
pp pptpd blahblah *
[code]....
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Apr 19, 2010
in gcc how to read a blank line ie a string of length 0.my code:
Code:
#include<stdio.h>
#include<string.h>
[code]...
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May 26, 2011
I want to know how can I add something to a specific line.. the output would be something like:
abc
def 123
ghi
Search for string "def" and add something to that line.
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Dec 14, 2010
I want to suspend/resume a thread. The library I am using is pthread.h.I am also running my application on linux.Is there any function in pthread. let me suspend a thread temporary?I have read a document in which it was mentioned thatthread does not support suspend/resume
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Apr 10, 2010
I have a very large data file, with 3 numbers in each line, ex. 3 4 5 ; 6 7 8.I want to add two numbers (0 and 1) at the end of every line, and a string at the beginning of the line. Does anyone know a efficient way to do so?
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May 4, 2009
Inside a loop i'm populating a string variable. Because csh doesn't have very good support for arrays I thought of doing this. I want to add a new line character to the end of the concatenation each time the loop iterates. Then at the end print this variable out.
I tried " and some resources said it was just a "". Neither work. What am I doing wrong?
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May 15, 2010
I have found this from a site [url]
Code:
But it does not work for me, segfault.
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Mar 29, 2011
Here is the issue. I am reading in a outside text file and putting in the string on that line into a char array that is already allocated.
Code:
int main(int argc, char *argv[])
{
[code]....
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Oct 30, 2010
I used a command Code:
grep -r err_sys ./
its output is
Code:
./tcpclitime.c:err_sys("socket error");
./tcpclitime.c:err_sys("connect error");
./tcpclitime.c:err_sys("write error");
./tcpclitime.c:err_sys("shutdown error");
./tcpclitime.c:err_sys("read error, n = %d", n);
[Code].....
Is it possible some how to replace all the occurrences of word err_sys by printf.
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Jul 26, 2010
i have an application that launches several pthreads, i know that the default size used by Linux is 8Mb for each pthread. However i would like to optimize the total memory usage by my application by decreasing the default stack size of each pthread to the needed resources. My questions:
- Are there any rules to set the pthread stack size.
- How to compute the memory needed by each thread.
- Is the malloc call inside a thread counted from the stack size of the same pthread?
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Apr 8, 2009
I am web developer I have this command find . -exec grep "Improve your score" '{}' ; -print for searching through files . I found this command but now i would like to tweak it to gain more out of it.
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Mar 12, 2010
I think this can be done using sed. Let's say I have file called, "orig.txt" with following contents:
Code:
[User Prefs]
Ignore Unrequested Popups=1
DevTools Splitter Position=500
History View Style=0
[Code]....
So basically if a line contains the word "Home URL" then go ahead and replace that *entire* line with the supplied *new* line.
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Mar 26, 2011
Do I have the convert the int to a string using stringstream then convert the string to a char? or is there a more direct way?Also is there a way to tell the length of a int?
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Feb 14, 2011
I wanted to find and replace a string from a perl file. I have written a script in bash which runs the following command.
perl -pi -e "s/$findstring/$replacestring/" testfile
where as $findstring = print F_WC_TMP"$line
";
and $replaceString = $line = join ' ', split ' ', $line; print F_WC_TMP"$line
";
But when I am running the above command, i think it is replacing the $findstring with the above mentioned string and hence it contains a $line, it is looking for the variable $line and not finding the exact string. I am confused about how to search for a string that contains $ in it and replace it with another $string.
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Sep 2, 2010
I have a line in a text file that has 40 random characters within a tag and i want to change the characters to a new set of 40 random characters (alphanumeric a-z 0-9 etc)
The line in the text file looks like this:
Quote:
How would i go about doing that?
Also second question same as the above but how would i remove them instead of replacing them?
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Apr 26, 2011
If I have a word in a text file and I need to replace it by another word (for example, i need to replace abc by fff) so what is the command I can type it?
I am using vi editor.
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