linux

Linux core dumps are too large!

Hey guys, Recently I've been noticing an increase in the size of the core dumps generated by my application. Initially, they were just around 5MB in size and contained around 5 stack frames, and now I have core dumps of > 2GBs and the information contained within them are no different from the smaller dumps. Is there any way I can cont...

How to define an alias in fish shell?

I would like to define some aliases in fish. Apparently it should be possible to define them in ~/.config/fish/functions but they don't get auto loaded when I restart the shell. Any ideas? p.s. if anyone is using or has used fish in the past I'd be interested to hear your comments as to whether it offers anything that bash does no...

How to include all objects of an archive in a shared object?

When compiling our project, we create several archives (static libraries), say liby.a and libz.a that each contains an object file defining a function y_function() and z_function(). Then, these archives are joined in a shared object, say libyz.so, that is one of our main distributable target. g++ -fPIC -c -o y.o y.cpp ar cr liby.a y.o...

trivial linux sound playback

The classical C program is something like: int main() { fprintf(stderr, "hello world\n"); } a classical OpenGL program is: open up a window setup ortho view draw a colored triangle Now, I want to do the most basic thing for sound in Linux. I want to: 1) open up speakers 2) send a bunch of data, meant to be interpreted at 40Khz, 3...

How do I compile on linux to share with all distributions?

I compiled a PHP extension on Fedora Core 12, but when I send it to someone using CentOS they get the error: "ELF file OS ABI invalid" I'm not sure what causes this running file provides the following info: ELF 64-bit LSB shared object, AMD x86-64, version 1 (GNU/Linux), not stripped An extension that loads fine provides the following ...

Compile for CentOS on Ubuntu

Can I install an older version of gcc/g++ (4.1.3) on the latest Ubuntu (which comes with 4.4.3) and use it to compile a .so which should run on CentOS? The binary compiled with the Ubuntu version of gcc fails to load on CentOS because of missing imports (GLIB_2_11, ...). I need C++ (including exceptions), so I can't just statically link ...

What is rc.status file in linux

Hi, I am creating a linux service , in the skeleton file it is mentioned that we need to run various rc commands(rc-status ,rc_reset) to update the service status. What does this actually mean. I have googled it but not able find many details. Can somebody help me ...

getnameinfo specifies socklen_t

The 2nd arg for the getnameinfo prototype asks for a socklen_t type but sizeof uses size_t. So how can I get socklen_t ? Prototype: int getnameinfo(const struct sockaddr *restrict sa, socklen_t salen, char *restrict node, socklen_t nodelen, char *restrict service, socklen_t servicelen, int flags); Example: struct socka...

Porting Windows C++ to Standard (Linux) C++ - WSAGetLastError()

I am currently porting some Windows mobile C++ code to standard C++. So I am trying to find alternatives for windows specific functions. I have had very little luck in finding a standard C++ function that can help me replace the WSAGetLastError() windows specific function. WSAGetLastError() returns error numbers for errors that occur ...

Get file name before the extension

I have some files in the same directory (in UNIX filesystem) that looks like: a.txt.name b.xml.name c.properties.name a.txt.name2 b.xml.name2 c.properties.name2 How do I get the string before the name or name2 part using some shell command? ie. the a.txt, b.xml, c.properties part? ...

What's the best way to build software that doesn't require the newest glibc?

I'm attempting to build a binary package that can be run on multiple Linux distributions. It's currently built on Ubuntu 10.04, but it fails on Ubuntu 8.04 with the following error: ./test: /usr/lib/libstdc++.so.6: version `GLIBCXX_3.4.11' not found (required by ./test) ./test: /usr/lib/libstdc.so.6: version `GLIBC_2.11' not found (requ...

PHPMailer, CC and Linux server

Hi, how do I add a CC mail address in PHPMailer running on a Linux server? AddCC method only works on Windows: http://phpmailer.worxware.com/index.php?pg=methods I tried with this method but the mail never arrives... I also tried with $mail->addCustomHeader('CC: [email protected]') without success. Thank you. ...

What is prepare_arch_schedule for?

I'm messing around with Linux kernel 2.4 and function schedule() in sched.c uses the macro prepare_arch_schedule, which looks really strange. What is that? Here's the relevant section #ifndef prepare_arch_schedule # define prepare_arch_schedule(prev) do { } while(0) # define finish_arch_schedule(prev) do { } while(0) # define prepar...

Preallocate memory for a program in Linux before it gets started

Hi, folks, I have a program that repeatedly solves large systems of linear equations using cholesky decomposition. Characterising is that I sometimes need to store the complete factorisation which can exceed about 20 GB of memory. The factorisation happens inside a library that I call. Furthermore, this matrix and the resulting factori...

Invoke web page from Linux C

Hi, I need to read all the HTML text from a url like http://localhost/index.html into a string in C. I know that if i put on telnet -> telnet www.google.com 80 Get webpage.... it returns all the html. How do I do this in a linux environment with C? ...

Using /dev/tcp instead of wget

Why does this work: exec 3<>/dev/tcp/www.google.com/80 echo -e "GET / HTTP/1.1\n\n">/dev/tcp/www.google.com/80 Is there a way to do it in one-line w/o using wget, curl, or some other library? ...

debugfs_create_file doesn't create file

Hello, I am trying to create a debugfs file using the debugfs_create_file(...). I have written a sample code for this. static int __init mmapexample_module_init(void) { file1 = debugfs_create_file("mmap_example", 06...

How to compare two floating-point values in shell script

I had to do a division in shell script and the best way was: result1=`echo "scale=3; ($var1 / $total) * 100"| bc -l` result2=`echo "scale=3; ($var2 / $total) * 100"| bc -l` but I want to compare the values of $result1 and $result2 Using if test $result1 -lt $result2 or if [ $result1 -gt $result2 ] didn't work :( Any idea how to do t...

Per Process Memory Calculation Alogrithm in Linux (say kernel 2.6 and above)

How do you calculate the linux process's Acutal Memory Usage and Not Virtual Memory Usage through the information supplied by /proc//smaps or maps or status or stat. To be more precise I need the heap usage only. I need to do this on an PowerPc based embedded system and hence I do not have utilities like exmap, valgrind etc. I understan...

continously add picture to video

Every x minutes I grab an image from a network-cam. Now i want to add this picture to an existing video file - on the fly. I don't want to keep numerous image files and then encode them once in a while with e.g. mencoder mf://@${LIST} -mf type=jpg:fps=${FPS} ... The video format/codec doesn't really matter, as long as standard tools ...