I have a shared library (built from C++ code) and a separate C program which calls (extern) functions from the said library.
Also one of the functions in that library needs to call a function in this C program by declaring it 'extern'. This sort of creates a cyclic dependency.
I am getting "unresolved references" error, as expected.
By issuing the 'nm' command on shared library (internally using one static library), the functions exposed by static library is also being listed, Which allows to use internal functions which is of course not intended. I have one static library having A(), B() and C() functions. Creating one shared library which has function XYS() that is using A() and B() functions from Static library. While doing 'nm' on shared library, all the static library function are being listed.
Static Lib:
#include<stdio.h>
void A(char *msg)
{
printf("
[code]....
In a c program the value of an integer variable is changing rapidly. I have to get the value of that variable at a particular instant from another program.
How can i do it without using a file?
When i tried with extern variable as
I execute the both .c file from 2 terminals but got only value 0 printed for both var_a and var_b all the time.
When I compile the following program with g++ I am getting error:
When I compile:
why I am getting this error?
I'm running gdb across a network using gdb server. I've got it up and running. However I can't see any source or variables for my code (in ddd /gdb). At start up gdb says (no debugging symbols found). I've got a g in my make file,
CPFLAGS = -Wall -Os -g -pedantic
I've tried loading symbols in using "symbol-file testarm", this sort of works in that I can view symbols but not names, e.g. if I ask dd to show x y and z, rather than
x = 10
y = 20
x = 30
It says:
display
10/20/30
Also ddd does not show anything in the source window, is there a way I can get it to show this? I think it's because I've started ddd with ddd arm-linux-gdb, as I'm calling a crosscompiler gdb. So can I tell ddd to point to the correct folders? What commands I need to set in gdb/ddd to view variable names (it's hard to keep track when it bunches them all together) and how to view my source code.
I decided to try making a programming language again after my last unsuccessful attempt, so now I figured how to write a good AST and it works great when the nodes are hard-coded into a test program. But to make a language out of it, I need a parser to build the tree according to an input file. I ran into a problem here:
YACC input file:
Code:
%{
#include "nodes/allnodes.h"
#include "Node.h"
int vars[26];
%}
%token SEMICOLON INTEGER VARIABLE IF WHILE DO OPAREN CPAREN OBRACE CBRACE
%right ASSIGN
%left NE
%left PLUS MINUS
%left TIMES DIVIDE
%% .....
As you might see, each nonterminal creates a Node* object and uses it as its value. The problem is that the literal tokens, however, don't return Node*'s and I don't know what to do. I would like to be able to convert literal tokens to nodes in the Lex file (which would avoid the problem), but the problem is with the assignment operator, which takes a Node* for the right-hand side and a variable name (not a Variable Node, because they just evaluate the the variable's value and you can't change the variable with them) for the left hand side.
I was going through some exercise given in my school. I have read the C book but I am not able to understand some part. That is static variable. What exactly is a static variable and what does it do? I saw in Linux Kernel Programming external and exported are also some thing. I am not getting the difference between static,EXPORT_SYMBOL,external variable types. If I make a kernel module then how will I make sure that my variable is visible to the kernel. Is this what it is all talking about? I have checked this page [URL].
View 2 Replies View RelatedI am trying to port c & c++ open source code onto embedded target(MIPS).It compiles fine on x86/RH4. When I try embedded platform specific tool chain as follows, I get following error:
I tried different combinations. It did not help. My idea is to port an open source code that works fine on X86/Linux to an embedded target based on MIPS.
Arm-linux-strip for removing the symbols from binary executable file after compilation. What exactly the symbols means.
View 1 Replies View RelatedI wasn't sure where to put this so if I need to move it just let me know.I have a strange problem that I cannot figure out. When I use gdb to debug our rpm-installed program, it says (no debugging symbols found) when it loads. Thing is, when I use nm on the program it can print the symbols, and even stranger is if I use gdb on the program before it is packed up by rpmbuild it loads the debug symbols just fine.Our program is built via the standard make using:GS=-g -Wall-pedantic and as I mentioned I can debug the resulting program. After the build, I package it up using:
cmd="rpmbuild -v -bb ptsnmp.spec --define "ver ${cmvc_release}" --define "rel ${cmvc_level}" --define "_topdir $rpmdir""When this package is installed via rpm, the binary on the machine shows all the debug info via nm, file shows it is not stripped:pt_snmp: ELF 64-bit LSB executable, AMD x86-64, version 1 (SYSV), for GNU/Linux 2.6.9, dynamically linked (uses shared libs), for GNU/Linux 2.6.9, not strippedyet when I try to debug it I get the no debugging symbols found.This is really taxing my brain and I am sure I am just missing something
I am using Centos 5.4 with gcc v4.1.2. If I take a bunch of .o files and I then link with my main.o to form an executable then this links and executes just fine. If however, I try to create an archive file (.a) using 'ar rus xxx.o yyy.o etc' and then try to link the resulting .a with my main.o then I get 'undefined symbol' linker errors and I don't understand why.
View 2 Replies View RelatedI have three keyboard layouts: en, ru and ua. Now I switch between layouts by pressing Ctrl+Shift (en->ru->ua->en->ru...). Here is part of my xorg.conf
Code:
Option "XkbRules""xorg"
Option "XkbModel""pc101"
Option "XkbLayout""us,ru,ua(winkeys)"
Option "XkbOptions" "grp:ctrl_shift_toggle,lv3:none,ctrl:caps,grp_led:scroll,caps:internal,compose:ralt"
I want to setup non cyclic switching with next sheme:
CapsLock - switch to en
CapsLock+Shift - switch to ru
CapsLock+Ctrl - switch to ua
I've read an xkb manuals and some articles about it but can't understand how I can setup xkb for non cyclic switching.
After installing Debian 8.2 I tested my multimedia keys and they all are correctly detected by xev and works as expected. Then I start to configure my keyboard. I need to use three keyboard layouts EN, UA and RU. By default I can switch between them using selected keyboard shortcut with following pattern: en→ua→ru→en→ua... But I want to switch layouts independently, using different keys for each layout, for example: qWCapsLock — enable EN layoutShift+CapsLock — enable UA layoutCtrl+CapsLock — enable RU layoutAfter googling and reading different forums I come to following solution (here is documents and discussion in russian). Create files
/usr/share/X11/xkb/compat/mycompat
Code: Select all
default partial xkb_compatibility "default" {
interpret Mae_Koho {
action= LockGroup(group=3);
};
interpret Zen_Koho {
[code]...
This works perfectly, but all multimedia keys now not recognized by xev and as result they does not work. I know that I can use xmodmap to map keys, but maybe same result can be achieved by fixing some of the newly created files or setxkbmap+xkbcomp command listed above.
Im doing a project,in which i have to add a script in c++ inorder to merge two or pdf files page by page or based on some headindgs.SO anyone can please suggest me any open source pdf libraries in c++ which provide functions for merging and splitting.
View 3 Replies View RelatedI am learning C++ and wish to include some Boost functions in my code. My machine is running Debian Linux with the pre-installed boost binarys.I have a couple of questions:How do I include the library in my C++ code as there are no cpp or h files only binary files (eg /usr/lib/libboost_regex-d.so and /usr/lib/libboost_regex-d.a)How do I comile the code. I am using DialogBlocks for creating forms using wxwidgets. The editor also compiles the code using the gcc compiler. Do I have to give an instruction to the compiler saying which file is requried and where to find it? If so, any ideas how this is done?
View 4 Replies View RelatedI am stuck with a problem to link static libraries with gcc. There is no problem with source files since I am able to compile in a machine where the static library is installed. I am compiling with the following: Code: :~/Emotion/pjproject-1.0.3/third_party 157% gcc -Wall -I/portaudio/include -o rec patest_record.c -L./lib -lportaudio-x86_64-unknown-linux-gnu
[Code]....
So I decided to take my first steps into programming with C + gtk. So far I have doneI loaded eclipse and ensured I had the cdt package Created a new C/C++ project called "play" Added a new source file called "Playfullsrc.c" Added the following to paths and symbols (output of the command: pkg-config --cflags gtk+-2.0)
Code:
/usr/include/gtk-2.0
/usr/lib/gtk-2.0/include
/usr/include/atk-1.0
/usr/include/cairo
/usr/include/pango-1.0
/usr/include/pixman-1
/usr/include/freetype2
[Code]....
added "/usr/lib/libgtk-x11-2.0.so" to GCC C Linker Libaries (I have cheacked and this file exists) When I build the project I get the error message "cannot find -l/usr/lib/libgtk-x11-2.0.soplayline 0C/C++ Problem" I have been following this tutorial: [URL]
I have 2 questions... I couldn't find answers by Googling (more precisely, by Blackling) and in GCC documents, so I'm asking here.
1. There are 2 flags for position independent code, -fpic and -fPIC. All the examples I read use -fPIC... so when is -fpic useful and what is the difference?
2. Some tutorials use "g++ -shared" while others use "ld" for the creation of the shared library. Why? Does it matter which method I use? Is there a difference? Why does nobody mention both options?
I've been trying for days now to build my first FastCGI application using gcc.
This is the output:
Code:
I believe I wouldn't have to refer to the lib path, but I added the -L flag to be sure.
The directory /usr/lib includes (among others) these files:
Code:
I have tried to follow these instructions. The files in the tar.gz archive provided by FastCGI.com no longer corresponds to the instructions there, but I was still able to run the ./configure and make commands so I believe FastCGI is installed.
But why can not the library be properly linked to? Really hope you can help me out on this one!
Just what it says in the title.
I can work in a 32-bit VirtualBox VM, but it's very inconvenient and I would rather work in my 64-bit desktop if that's not too difficult.
These are all the lib32 packages I have installed code...
This post isn't really asking for a tutorial, but rather asking for some ideas. I've come up with a few ideas, but they seem cumbersome and unnecessary, so I was wondering if someone with more experience than me could out. Also, my explanations suck, but I'll try to do my best. So say I have an executable called X. At some point during its execution, X loads and uses (using dlopen and dlsym) a library called Y. In Y, there a bunch of functions that call the function called, for example, void *special_malloc (size_t). These functions come from another linked library (linked during compilation) called Z. Problem is, special_malloc contains some static variables within its scope, and when those variables are reset midway through a program, an invalid free occurs (special_malloc uses garbage collection). Now, what I want to happen is that whenever lib Z calls special_malloc, it instead calls the special_malloc defined in the executable X, so that these static variables are retained. Keep in mind that I have control of the Z library, meaning I can edit the source to fit my needs.
View 2 Replies View RelatedI know, it's a common Problem but I just can get it right. Im pretty new on Linux and some Commands confuses me a lot. Though, I managed to made me a root account to read any files on both HD. But I still cant write on the external HFS+ formatted HD. ReadOnly Filesystem. I cant set up an internet connection in order to install files. Is there some workaround?
MacBook 5.1, Live-CD Ubuntu 9.10, external HD via USB
I accidentally unplugged my external hard drive during a format and now it is unrecognisable by my Ubuntu system.
View 4 Replies View RelatedI'm using debian and, though i'm new to c++, i'm writing a program using it which needs some HTTPs functionalities . I found these libcurl libraries could help me but I haven been able to use them from my program. I installed them (power trio configure -make -make install ) but i guess i'm doing something wrong ... i feel like i should copy or link them somehow in my project (besides the include sentences in my code). I hope you could give me a hand with this im quite lost
View 9 Replies View RelatedI am using the API libpcap in order to filter the traffic of the port 53 from my PC ro other PCs, in other words the DNS traffic.I want to get more information about the DNS traffic that is being sent to the DNS server, in other words the queries. So far I have no idea how to read the information data or payload of the UDP package in order to read the content of the traffic for example if there is any PTR, A, MX, etc Resource Record.According to the RFC 1053 there is a header that is possible to use in order to easily get this info.
View 5 Replies View RelatedAny good tutorial on sharing dynamically allocated objects across shared libraries in the same process and between shared libaries and main(). In particular, I need to know what creation and destruction sequences are valid when libraries are being loaded and unloaded. For example, is it valid to allocate an object from inside a shared library procedure, and then delete that pointer from a different module, especially in the case where the allocating module has already been unloaded.
I imagine there might be all kinds of problems with this. Although my preliminary tests seem to work most of the time, I get crashes from time to time, but I'm not sure if they're caused by memory management or by threading issues. I've been restructuring my code to use a global context object to manage object creation and destruction from main(), but I'd like to find a clear exposition of the specific issues I'm dealing with before I go too much further.
I have been a predominant Windows user for a long time but shifted to Ubuntu recently. I was just trying out a few basic C functions when i realized that the "conio.h" header file isn't included in the libraries and therefore i was unable to use the "clrscr()" function.
I downloaded a tarball which contained the necessary library and header files including conio.h. Once extracted, i specified the location and included in the program as " #include "path to the header file" ".
I still didn't call the "clrscr()" function, and it compiled successfully. Next i edited the program to call that function and it gave the following error...
How i can add new libraries in the future?
Since I read that executing a library could return its version number, I ran "/lib/libc.so.0" on uClinux, but it triggers an error.I'm told that random libraries are not directly executable. Does someone know what a random library is?PS: In case that matters, here's the short version of the error:
Code:
Undefined instruction
<5> - May be used to emulate instructions that are not defined for
[code]....
Why many Linux distros are trying to use always the latest versions of the libraries and don't save the old libraries for compatibility? I mean, I can see libtiff for example, i can found a libtiff.so.5 on my /usr/lib, but doesn't store a libtiff.so.4 or 3 just for binary applications or games. For this example, I need libtiff.so.4 for uplink.
That should happen too on the old version of sims for linux, some ID games or others.What's wrong with storing old libraries? PD: Yay, my first post on 3 years!
I use OpenSuse 11.3, Eclipse Elios for C++. What do I have to do for using boost? I put #include <boost/regex.hpp>, but it can't find the file. What variable do I have to use?
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