I am trying to use the TCP option TCP_USER_TIMEOUT which was added to linux in 2.6.37.
Apprently my C source includes the netinet/tcp.h instead of linux/tcp.h. And TCP_USER_TIMEOUT is defined in linux/tcp.h and not in netinet/tcp.h I read here that user space apps should NOT include any header from linux/ (like in this case linux/tcp.h). But that link doesn't explain why.
Your source is incorrect, and a bulletin board is hardly a definitive source.
You should not include header files from the linux directory unless you are trying to include linux specific functions which are only to be found by including header files from the linux directory.
In relation to TCP_USER_TIMEOUT, the man-page for TCP notes in respect of many of the options 'This option should not be used in code intended to be portable'. Whilst it does not note this in respect of TCP_USER_TIMEOUT, it is a linux-only option as far as I understand it.
However, in this case:
$ grep -r TCP_USER_TIMEOUT /usr/include
/usr/include/netinet/tcp.h:#define TCP_USER_TIMEOUT 18 /* How long for loss retry before timeout */
/usr/include/linux/tcp.h:#define TCP_USER_TIMEOUT 18 /* How long for loss retry before timeout */
at least in my include files, it's present in both files. Perhaps you need to update your includes.
Related
What is the header file for vsnprintf in the kernel? Can anyone please tell me this, I have kernel 5.14 and I am not sure what headers are default on my system. I have a number of different kernel headers installed, these are:
linux-headers-5.11.0-25
linux-headers-5.11.0-40
linux-headers-5.11.0-25-generic
linux-headers-5.11.0-40-generic
linux-headers-5.11.0-38
linux-headers-5.11.0-38-generic
Which one should be the default? But i like to ask what is the header file for function vsnprintf?
Taking a look at the source code for Linux v5.11, the correct header seems to be linux/kernel.h. It's the same file for Linux v5.14.
To check which headers you should use for your currently running kernel use the command uname -r which should tell you the correct version. You can then compile using those and an appropriate Makefile: see the documentation for more info.
I'm trying to include a folder that contains a combination of around 60 .h and .hpp files. This folder contains libraries for programming robots with a Wallaby (a mini-computer-like device) for Botball competition. include is located in the same place as main.c (inside code). Up until now, this is what my header for including libraries looks like:
#include "../code/include/accel.h"
Just like accel.h, I have 60 other .h and .hpp files inside include. So, coming to my question, do I need to type out all the 60 header lines? or is there a way to include the include folder.
I'm using Clion for this project, if I can't include the folder itself, does anyone know of a shortcut in Clion to include all the files in include.
I was also thinking of using some sort of placeholder for the folder name and only specify the file type. So, for example: #include "../code/include/(generic placeholder name).h". I have no clue if something like this exists.
I would also request you to keep in mind that I'm a beginner to programming, so please keep your answers simple.
This is just for some extra info:
The Wallaby is a mini computer to which you would connect your sensors, motors, servos and cameras in order to control a robot for the Botball competition. Usually, one can connect to the Wallaby either via Wifi Direct or a cable and write programs on it directly through an online interface (not entirely sure of the word for it, but you just type in an IP address in your browser and it brings up an interface where you can make projects and code). All the code written in that interface saves directly onto the Wallaby. Here the default include statement is #include <kipr/botball.h>, so I'm assuming that botball.h (which is located on the Wallaby's storage) has all those 60 libraries consolidated in it. I got the include folder that I'm using from GitHub. This link was provided to me by one of the Botball organisers. So the main point in me trying to download the library is so that I can write and successfully compile code even when I'm not connected to the Wallaby. Hope this provides some relevant context.
Thank you for your answers!
What I'd do is
Create (maybe with scripting tools or a specific program) a "all.h" file which includes all the other header files
#ifndef ALL_INCLUDED
#define ALL_INCLUDED
#include "accel.h"
#include "bccel.h"
//...
#include "zccel.h"
#endif
Include "all.h" in your main file
#include "../code/include/all.h"
You can create "all.h" automatically every time you build your code.
CLion is an IDE for Clang and GCC. These compilers are instructed to search paths for include files by specifying -I<path> command line arguments. Any number may be specified, and they are searched in the order given, and the first match found is the file that gets included.
I am not familiar with CLion specifically but no doubt it has a dialog somewhere where you can set header file search paths.
Edit: It seems that CLion may not make this so straightforward. I understand that you have to add then via CMake: https://cmake.org/cmake/help/v3.0/command/include_directories.html#command:include_directories, but after that, the IDE will not recognise the header in the editor and will warn you of unrecognised files and will not provide code comprehension features. I believe it will build nonetheless.
When trying to compile a Pro*C based batch file, the process "proc" stucks at 100% of 1 CPU core and the memory starts growing to a point where the system needs to OOM kill the process (the machine has 16GB Memory and the process grew up to 9GB).
Has anyone seen this behavior before?
As an aditional information:
-The mk is the one from the instalation of the main package
-The .pc files are the original files (I've tried to compile several, such as dtesys.pc)
-The Libs are correctly compiled
-The environment variables are correctly set
Yes, it is limits.h because it includes itself recursively on line 123:
/* Get the compiler's limits.h, which defines almost all the ISO constants.
We put this #include_next outside the double inclusion check because
it should be possible to include this file more than once and still get
the definitions from gcc's header. */
#if defined __GNUC__ && !defined _GCC_LIMITS_H_
/* `_GCC_LIMITS_H_' is what GCC's file defines. */
# include_next <limits.h>
#endif
So, the solution is to pass parse=none option to Pro*C precompiler:
proc parse=none iname=filename.pc oname=filename.c
Or, a second option: you may first precompile your source with c precompiler to get pc file:
cpp -P -E yourfile.someextension -o yourfile.pc
Then you will get limits.h parsed without recursion.
-P option is needed because Pro*C is the program which can be confused with linemarkers.
-E option is needed because Pro*C is the program which can be confused with non-traditional output.
I am running Ubuntu 10.10 on an IBM R51 machine. When I access list.h to read it(manually/humanly) I open /usr/src/linux-headers-2.6.35-22/include/linux .
But when coding a C program in terminal, I cant invoke any #include because it is not in the default /usr/include folders.
When I change the statement to reflect the path by typing #include "/usr/src/linux-headers-2.6.35-22/include/linux/list.h" it returns errors as list.h in turn calls other header files which are mentioned as located in "linux" folder
The header files are as you must be aware:
"linux/poison.h", "linux/prefetch.h" and "asm/system.h"
So if I have to copy each, I can but prefetch in turn calls other dependencies, which are not present in /usr/include directory. I hope you understand.
How can I solve this problem?
Are you sure these headers are really what you need ? The standard C headers should be under /usr/include
Anyhow you need to pass the header search path to the compiler via the '-I' flag.
Pass the path via -I
-I/usr/src/linux-headers-2.6.35-22/include/linux
Then in your C code
#include "list.h"
Link to GCC manual & preprocessor directives
The header files you are using are designed for internal use of the Linux kernel. They were not designed to be used by a userland program.
If you MUST use these headers (the Linux kernel list implementation is brilliant), copy the headers into your program source directory. Copy each file that is referenced, edit each one to remove whatever assumptions exist about being used in-kernel, and recurse until you're finished. I might suggest to make your own prefetch() macro that simply does nothing, rather than try to untangle <linux/prefetch.h>. Do the same for <linux/poison.h>, and untangle <linux/types> and <linux/stddef.h> (not too hard here :) as best you can.
And also be sure you license your project GPLv2 (and specifically GPLv2, the Linux kernel's COPYING file is quite strict that GPLv2 is the only license that applies; there is debate whether the GPL allows specifying only one version, but that is the license Linus chose ages ago, and the license that is valid on all files unless specified otherwise).
adding -I/usr/src/linux is a no-go, since unsanitized header files are not meant to be used from user programs
you could manually copy list.h to your own project and sanitize
or use a library that is specifically for userspace and provides the same functionality (since you already used libHX elsewhere, you might want to continue reading into the linked list chapter)
So I start reading the book http://lwn.net/Kernel/LDD3/ to write device driver
The problem is the book used 2.6.10 while I'm using 2.6.35.X (on Ubuntu) and "config.h" is missing. I googled the problem and it turned out that config.h is removed.
http://stephane.lesimple.fr/wiki/blog/kernel_2.6.18_linux_config.h_problem suggests 3 solutions and the first 2 don't work to me ( I don't have autoconf.h ). The 3rd solution is the one that is over my head. If anyone can explain the 3rd or has other solutions, I'd appreciate.
Thanks
All -imacros file and -include
file options are processed after all -D and -U options1.
Each (of the three) option is a way of pointing GCC to a text file with a list of preprocessor defines.
To use option 3, -imacros a_file , there is still a need for the file a_file , (ie: autoconf.h), the file with the macros or configuration definitions. On this system it's /usr/src/linux/include/generated/autoconf.h
l /usr/src/linux
lrwxrwxrwx 1 root conman 23 Nov 29 19:37 /usr/src/linux -> linux-2.6.35-gentoo-r12
As you can see, this file can occur in 2.6.35. It seems that maybe configuringi the kernel makes this file; because the content of this file looks tailored to the current kernel. This looks like a file declaring which drivers are compiled-in(as apposed to compiled as modules).
So:
First check for the file find /usr/src/linux/. -name autoconf.h
If it is not there, then configure the kernel (then check again)
Change CFLAGS in the device driver's Makefile to include -imacros /usr/src/linux/include/generated/autoconf.h
CFLAGS+=-imacros /usr/src/linux/include/generated/autoconf.h
Comment out #include <config.h> from the driver sources.
1 "3.11 Options Controlling the Preprocessor," GCC Reference