Programming :: Real Difference Between System Calls And Normal Function Calls?
Oct 26, 2010
What 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.
I 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.
I'm trying to produce a alphabetic, non-repetitive list of all System service calls in all c files located in a folder. Here's what I got so far. grep -ow '[A-Za-z]*SYS[$][A-Za-z]*' *.c | sort Which produces all system service calls in alphabetic order I just need to find out how to make it non-repetitive.
I am working with fedora 6 , i386 architecture.I am trying to write on keyboard port via program.On inspation i come to know that 0x0060 to 0xz006f are used for keyboard in linux 2.6 kernel in the i/o space from kernel.
I need to write a script. In which, the 2nd part commands need to run under another bash shell environment.The enter_antoher_bash_env.sh will setup a new shell environment, call "bash". The rest commands need to run under the new env. (I cannot change this script too. )If I run these command one by one manually, it works of course. If I put them into a script, enter_another_bash_env.sh won't return because it calls "bash" command inside.
I've been receiving a ton of calls from telemarketers and political callcenters. What would be the simplest way to use Ubuntu to automatically drop calls incoming from blacklisted numbers?
I have Comcast Digital Voice service, which is technically VOIP but I think it interfaces with modems themselves just like any other phone service would. I have a dedicated Ubuntu server sitting next to a phone jack already, so I'd like to use that if possible.
I've seen FreePBX and Asterisk, and hear that they can do the job. However, I haven't been able to tell just how easily they could be set up. It sounds like they might require me to get rid of all my phones and use soft phones instead... Does anybody know if it is as simple as buying a voice modem and configuring a PBX software to interface with it?
I've implemented a few custom system calls in my Ubuntu kernel, but I'm having some issues with the return values. Each function returns a variety of non-negative integers depending on which error is encountered. However, when I'm testing the system calls, the only negative value that gets returned to the user program is -1, regardless of what I have in the code.
Is there some special path I have to take to get the proper return values?
I would like to trace a user's activity by monitoring system calls. Is there a way to use strace such that at startup it will begin tracing all system calls? Or is there any other method to automatically trace the system calls used during a user's session automatically without having to call strace manually?
I'm new to C language and some help finding places in the following code where a system call is made and error checking is not done. I found one but since I don't know C language at all I'm not exactly sure what else to look for. Link to my file: [URL]...
I found one and added error checking: if (setoutpipe){ //Changes: Added error checking to the system call close() //Orginal Code: close(pidefd[1]); if(close(pipefd[1] != 0){ fprintf(stderr, "Could not close piple. "); exit(255); }
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?
We recently ported an application over from IRIX to Linux, specifically SUSE Enterprise 11 and gcc (glibc 2.9). On IRIX there was a library trace utility call 'par' that allowed me to execute a C program and trace all the library calls it made, tracking how much time was spent in each call. I have been trying to find something similar for SUSE. I have found the ?trace programs (strace, ltrace, and ktrace) none of which is default installed on SUSE 11.Does any one have a suggestion on which ?trace to install and use or is there something else out there better?
Is there a way to hook calls to new/malloc, delete/free in C++? I tried the following methods: LD_PRELOAD -> fails for malloc, because dlsym seems to depend on malloc -Wl,--wrap,malloc -> doesn't work for 'new' gcc hooks -> doesn't work always, e.g. for uclibc there are no hooks Are there any other methods I could try?
I'm trying to write a C program that extends an array to any user inputed size.
Code: if (arraysize == 0) { arraysize = (int) pos + 1; a = (int *) calloc (arraysize,sizeof(int)); for (i = 0 ; i < arraysize ; i++ ) a[i] = -1; code....
The program dumps with that sequence of inputs everytime, but might dump an input before or after if different positions are requested. Interestingly, when I tested pos = 2000..2008, I got no dumps. So is realloc somehow trying to extend the array into bad space?
I am trying to port some "C" code from Solaris to Linux. I have a Dell PowerEdge R610 with an Intel Xeon E5504 quad core processor running Red Hat Linux Enterprise 5.3. I am compiling in 64 bit mode. I have managed to get the code compiled and linked, but when I attempt to execute it, I get a core dump in one of the C library calls (like strcpy or printf.)
I have a static library that contains our own code that makes the call to the C library. If I move the library method into the source file with the main method and rename it to be certain that I am executing my method instead of the method in our library, the call succeeds. Eventually another static library call is made that results in a core dump in the shared object. I compile my library code into a static library with gcc as:
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()
I want a log or live data that discloses the system calls an application makes. I have used strace but can't find a guide for it that is decent. I'm interested in knowing the calls made after user intervention like opening a menu and so on. If you run (strace application_name) it is static. What good is this? When does strace make this file? When is this log produced?
I have installed linux on a virtual machine in Oracle VM VirtualBox because I want to run linux while running windows at the same time. I was wondering if there is any difference between a real linux system and a virtual one for learning purposes.
I while back I tried installing Skype form the software centre but for some reason it wouldn't work. Now, with a fresh install of Lucid, I see that Empathy comes pre-installed and allows video chatting. Is it worth setting up a account? Does anyone have experience with Empathy?
I have a really bad delay on skype. The calls start off fine, but quickly the audio falls behind. I've messed around with a bunch of different audio settings and nothing helps, only completely removes audio.
After I installed Lucid on my Netbook, I have different problems with ekiga.
First of all, some information about my ekiga account:
In ekiga I created a SIP-Account with a usual landline phone-number, my voip-provider is 1&1 (in Germany). In ekiga the account is named "Standard%limit", because I cannot register my sip-account without the "%limit". If I leave the "%limit" out, I get the message "Could not register (Forbidden)", but here on ubuntuforums (or maybe on launchpad) I read about the "%limit" as a workaround. Maybe it has something to do with my problem, I don't know.
Now, this is my problem:
Ekiga does not accept incoming phone calls after a few minutes after launching ekiga. Well, let me describe it this way: Usually ekiga plays a ringtone and shows a message whenever there is an incoming call. However, ekiga only behaves as described and expected just after launching ekiga. A few minutes later, lets say five or ten minutes, ekiga does not accept incoming calls anymore. I tested it with my mobile phone - when I call myself on the landline with my mobile phone, I expect ekiga to play the ringtone and show a message that there is an incoming call. However, ekiga does not do anything and after a few seconds the call is terminated automatically. But it is not the same as if ekiga is not running because if ekiga is not running I get the message that the subscriber is not available.
I am building an android, from the source using make command. I want to achieve simple logging while this make is happening.
Aim:
I want to look/log for internal system calls that are being made after i do 'make' command in bash terminal. So that after the make is done, i can look and study the internal method/file calls made while make was happening. In this way i will come to know how the actual building process works.