How does a C program start in linux? Is main() the first function called in the a c application by kernel. I understand it is the first called function written by the application programmer, but the question is to understand the what all kernel does and what all functions it calls before calling main()
View 9 RepliesI know there is a way to call winapi in runtime in windows. I want to ask how can I call a system call in gcc in runtime (when I don't know what it can be)? I don't mean syscall that I think is for calling only system calls and not library functions.
View 4 Replies View RelatedI feel like there should be a cleaner way of doing this. I have one file, for example "a.cpp", calling a function from another file, "b.cpp". Currently I have it set up so that header for "b", "b.h", has the declaration of its functions. And then I'm just including "b.h" in "a.cpp". Do I have to include the "b" header file in "a" to be able to call a function from "b"? Or is there a better way I could be doing this? Like doing something different at compile?
View 7 Replies View RelatedI'm trying to call some kernel functions from userspace, but I'm not sure if I'm doing it right. The functions control a pulse width modulator on an embedded platform. To pick one at random, the function:
Code:
struct pwm_device *pwm_request(int pwm_id, const char *label);
is defined in linux/pwm.h, and the implementation uses the macro EXPORT_SYMBOL(pwm_request), so I should be able to call this from user-space... right?
Anyway, I've got linux/pwm.h to #include in my source so the compiler knows what it's doing, but what do I link against? The only place in by kernel build tree where I can see a symbol pwm_request defined is in object files like vmlinux.o, built-in.o in the directory, etc. which I don't think I should be linking against.
In my project,Login window is created as a Dialog box.So when i tried to call the constructor of Login from Main it was generating an error regarding the arguments passed.I have not used any arguments when i called. when i looked at the code, the function was declared as public Login(java.awt.Frame parent,boolean modal)so when i call it from main(),what am i supposed to do ?
View 3 Replies View Related(For function arguments): Scalar arguments are passed by value, which means that a copy of the argument is made for processing in the function, and changes to the argument in the function won't be reflected back to the calling program. Objects though, are passed by reference: any changes to them in the function are reflected in the calling program. What sense does this make? Why have they done this?
View 3 Replies View RelatedI have a new problem; i want to call a subroutine's fortran which have a function in the argument and the compilation ran properly, but when i execute the program this shows me an "Segmentation fault". This is my c++ program:
Code: //Main.cpp
#include <stdio.h>
#include <iostream>
[code]....
I wrote a multithread program(c++,gnu gcc). it contains a main program and plugins. some functions in plugins use sleep(). Using these functions in threads cause freezing program. in other word thread sleeps but dosn't wake. How can i use sleep() in my plugin functions without this problem?
View 3 Replies View RelatedWhat is the real difference between system calls and normal function calls. Ultimately function calls too would be passed to kernel for some or the other work.
View 7 Replies View RelatedSay, i have a main program called as vauto.f ( written in F77 ) and complied with gfortran and run successfully using the help from Mr. Colucix ( Many thanks, Mr. Colucix ). Got an output file (RFILE) after running this program. I want to post process this out put file giving this as input to some other program, that is written as sub routine in a separate file, four.f. I tried to incorporate this subroutine into the main program v.auto.f and ran into several compiling errors and before saving those errors my system went dead so could not post here the errors ( sorry about that ).Think myself as a very new programer. what would you advice me to do??
==a. create an object file of that subroutine file and link that to main file and compile both of them and get output fileb. After obtaining the result file from the first program (RFILE), run this subroutine ( but how to do that?? is my question bugging me for more than 4 days, tried different things and met with failure ).=====
For our kind attention, have attached the main program (vauto.f), RFILE, four.
it possible to access main program function from dynamicallyinked library in c language?For example:main.c:
Code:
#include<stdio.h>
void func()
[code]...
when i call the "system()" function from my C program everything works well, but when i try to call it from a cgi C program it doesn't work. the server log tells me this is a permission error.i have chmod'ed 755 the cgi program but it still does not work.
View 5 Replies View RelatedI wrote the following script to organize my music files and to learn a bit more about bash.
My problem is, now that I'm almost over the first version, that functions which are surely spelled correctly and were recognized in the past, are giving me the "command not found" error!
Code:
#!/bin/bash
# This is a script for moving tagged files into organized directory trees.
##### Variables
filenum=0
[Code]....
I'm running 10.04 on a Fujitsu Siemens Amilo Pi 1505 laptop. Normally, when I plug my headphones in, all sound is diverted to them. I haven't found anything in sound preferences that changes this.(Under Sound Preferences, Output tab, there's a dropdown called Connector.It has options: "Analog Heaphones", "Analog Output" and "Analog Speakers" but they don't seem to make a difference.) I'd like to leave my headphones plugged in all day and setup my machine to play all sounds through my speakers (including Skype ringing), except Skype calls, which should play through my headphones. Skype has a feature to split the ringing and call sounds, i.e. play them on different devices, but the only option in each dropdown is "PulseAudio Server (local)".
View 1 Replies View RelatedIs it possible to define functions within other functions in C++? I know it is the case in other languages.
View 2 Replies View RelatedI am trying to take argument from command line ic a Cprogram an give that argument as an argument to a script file which is called in that C program.Is it possible for example:
my C program is:
#include<stdio.h>
#include<string.h>
#include<stdlib.h>
[code]....
I want to fill that blank with thevalue of argv[1] such that it will act as an argument for temp1.sh.
SuSE 11.2, KDE 4.2 after logging in to runlevel 5: I have a process which is calling every 5 seconds /sbin/usbmod (which doesn't exist, hence I get lots of errors when I go to the screen with the boot messages). I want to know which process does the calling. How can I find out?
View 4 Replies View RelatedI need help as I am not proficient with Linux C++ Programming. There are two parts which I need to do in the coding provided below.
1. Produce the program so it can output the word "Hey there!" and wait two minute and print the word "See you later!".
2. Produce the program that will output the text "Cool" every 20 seconds by setting a periodic task.
Quote:
#include <linux/kernel.h>
#include <linux/module.h>
MODULE_LICENSE("GPL");
int init_module(void)
{
printk("Hey there!
[Code]...
I have a question about calling an asm function from C....It doesn't work unless I create an asm variable to hold the value of the function in....Why?Here's the code that doesn't work...
asmfile.s - version one Code: .section .data
mydata: .ascii "this is the message!
.equ mylen, . - mydata
[code]...
I am doing a web site program and what I need is to call a C program in the PHP cloud.Do u think it would be possible? The web site would get the user input from PHP UI and pass to the C program , the C program would process the function with the user input and output the a PHP page.
View 2 Replies View RelatedNone of my daemon scripts work now, and the startup process displayed errors. Should I reinstall the OS and start from scratch, or is there a way to recover these files? Is there a way to rebuild the files I deleted?
View 2 Replies View RelatedUpon booting, how can I know which program starts first? Also, how can I force something to start after something else? For instance, how do I make sure that everything I deem as "not urgent" to load after the GUI and also how do I make sure things like firestarter start before fail2ban, etc?
View 2 Replies View RelatedI want to call c exe from java source code and i want to interact with the c program during it's execution, i am able to send the parameters to c program but i am not able to interact with it.
View 3 Replies View RelatedI have found a weird behaviour on a linux application. A tty seems to get closed without calling close. The program is (very simplified) as follows:
Process 1:
configure_signals()
read_config_files()
create_threads()
wait(forever)
Thread 1:
fd=open(/dev/ttyXX)
usleep(a while)
config(fd)
I have spent quite a lot of time on this problem. It seems like the file is sometimes closed when reaching config(fd), but removing the usleep(a while) seems to remove the problem.
I have a bash script that changes the iptables.Now i call this bash script in my php code.When this bash script is running the part of code that contains iptables instruction is not running because we need to be in superuser mode(root)
View 14 Replies View RelatedI'm trying to call some Fortran 95 code in C, but I'm having problems with integers not having the same value in C as in Fortran, and changing values upon each run of the program. I think it has to do with the integer type, but I don't know how to fix it. I'm running Gentoo x86. Here are the files I've got:
foo.c:
Code:
#include <stdio.h>
extern int qux_();
main() {
[code]....
What is the difference in perl between:
'function();'
and
'&function();'
with and without ampersand.
i use the sockaddr_in like this before calling bind(), it works good.
Code:
sockaddr_in serveraddr;
serveraddr.sin_port=htons(5000);
serveraddr.sin_addr.s_addr=htonl(INADDR_ANY);
serveraddr.sin_family=AF_INET;
[Code]....
I need to include variables in a system() call. This is that I have:
[code]#include <iostream>
#include <stdio.h>
#include <stdlib.h>
using namespace std;
[Code]....
P.S.: I know this is a pointless redundant program, but it's part of a larger project learning process.
I have a problem in making multiple calls using PJSIP. I registered different accounts that implements IAccount and added that in the CallManager. When i try to make the calls from the same CallManager, I could able to make the first call. When second call is made the first call got cut and it is alerting and the same for the thrid call..Could anyone help me in this regard.
Note: Calls has to be made from different numbers to different destinations. Is it possible to make multiple outbound calls simultaneously from the same instance of CallManager?