Coming from Java environment, I feel I got spoiled a lot when it comes to documentation. In C, using Eclipse, mouseover putchar() shows:
__CRT_INLINE int __cdecl __MINGW_NOTHROW putchar(int __c)
{
return (--stdout->_cnt >= 0)
? (int) (unsigned char) (*stdout->_ptr++ = (char)__c)
: _flsbuf (__c, stdout);}
While all this is terrific, I was wondering if any IDE includes more information about the specifics of what a given function does, ie, "prints a character to the output device"? Something similar to this as part of an IDE would be awesome.
Is there a way to get this level of detailed as part of Eclipse or any other IDE?
The question, obviously is not about putchar(), but rather is about a general approach to documentation using C programming language.
NetBeans will show you the man page inline: http://netbeans.org/kb/docs/cnd/navigating-editing.html
I don't have a solution for eclipse or an IDE, but my approach usually involves googling the function's manpage. eg, man putchar, which you've already found.
I'll also suggest this, at the risk of downvotes: The IBM C documentation is, in my experience, really good. Often it has real working understandable code examples and everything.
Now, IBM C is different from GNU C, so there are differences or features that do not apply to gcc. That said, Take a look at its page on the putchar() function.
There are plenty of things to complain about in C99, but it is still the authoritative reference and imo the best source for answers to the question, "what does it do?"
MS Visual Studio wraps a little skin around the C99 bones.
And MSDN goes further: docs on MSDN are beginning actually to resemble real papers by real writers that communicate useful info to a wide audience of neophytes and pros alike.
All credit goes to Let_Me_Be.
The following link provides a complete solution to what i was looking for
eclipse.org/linuxtools/projectPages/libhover
Related
This is my first question so please bear with me, I'm trying to find a good compiler to parse the following standard, I've tried asn1c and I wasn't able compile it successfully, the problem is that I didn't get any error, I tried with "-P" and there was no output, this is what I did
sn1c MAP-ShortMessageServiceOperations.EXP -P
The files in the link have been generated by SIEMENS and for some reason they are not the standard ASN.1
The question is how can I compile all these ASN files with asn1c or any other asn compiler?
and also I've tried snacc and didn't get anything useful from it either.
I'm trying to write a C application that will be running on Red-hat Linux
A great place to start is http://www.itu.int/ITU-T/asn1/links/index.htm which list several ASN.1 compilers (both free and commercial).
You can also try your specification in the free online compiler and encoder/decoder at http://asn1-playground.oss.com.
For 3gpp specifications, you are likely to be better off using a commercial tool rather than one of the free tools. OSS Nokalva offers free trials of its ASN.1 Tools at http://www.oss.com/asn1/products/asn1-download.html.
http://www.itu.int/en/ITU-T/asn1/Pages/Tools.aspx mentions two free ASN.1 compilers, one of which is
http://lionet.info/asn1c/compiler.html which is FOSS and seems to be well received (http://lionet.info/asn1c/quotes.html)
The second “free” compiler listed seems to have gone commercial (http://www.oss.com/asn1/products/asn1-c/asn1-c.html), BUT the same company offer a free online encode/decode service at http://asn1-playground.oss.com/
I can’t figure out if this one is free or requires purchase - http://www.obj-sys.com/products/asn1c/index.php
This one is FOSS and might be worth examining - https://github.com/ttsiodras/asn1scc
Another tool for 3GPP specifications is online encoder/decoder http://3gpp-message-analyser.com It supports UTRAN RANAP SABP RNSAP NBAP PCAP RUA HNBAP, E-UTRAN S1AP X2AP M2AP M3AP
You can also find various free online ASN.1 decoder here:
https://www.marben-products.com/decoder-asn1/
I hope it helps.
Anto
I came across this compiler that works well for generating C code from ASN.1
https://github.com/ttsiodras/asn1scc
There is also a nice introduction that will get you started, here:
https://www.thanassis.space/asn1.html
This is the only compiler that worked for me so far.
I am learning c programming in Linux. There are a lot of linux functions I need to look at. Is there a website that gives me the details of the Linux functions?
Are you referring to system calls in Linux? There are lots of sources. The man pages are your good friends in this regard. Try also http://linux.die.net/man/2/syscalls. I am sure there are lots of others.
The standard reference by far is "Advanced programming in the UNIX environment" by Richard Stevens. Unfortunately this book is quite old, so there is a revised edition by Eric Raymond, which covers new stuff in Linux. This -- more than anything else -- is the de facto standard for learning "old world" systems programming in Linux. (And most other *ixes, there are of course differences, but you won't notice them until you're much more advanced, and by that point you'll be familiar with the man pages and know where to look.)
You can look at the LSB (Linux Standard Base) website:
http://www.linuxfoundation.org/collaborate/workgroups/lsb
Here are is the last Linux Standard Base Core Specification:
http://refspecs.linuxfoundation.org/lsb.shtml
IMHO http://linux.die.net/man/ is the easiest to get to start with.
It has useful sections introductions, so you can get your bearings
Most usefully are the one line synopsis pages, e.g. http://linux.die.net/man/3/
This shows the scale of what you are asking, and also lets you search for a key word describing each function within your browser, which can be very handy.
As has been pointed out, it is not the most up-to-date, but IMHO it is easier for a beginner to use than the alternative I've seen (not that there can't be something better, just google doesn't bother to show it).
Also worth trying apropos or man 3 -K or aman -k`
I find the glibc manual very good. It is organized by topic and contains concise background material and examples. It'll allow you to get the big picture and serves as a reference. Manpages are a quicker way to access function descriptions but there are only useful if you already know what you are looking for.
I am looking for ANSI C HAT-trie implementation released under some free license. I have not found one. Can you point me to some standalone implementation or a program that uses
HAT-tries to get at least slight idea how to implement it the roght way, please?
The original paper on HAT-trie can be found here:
http://crpit.com/confpapers/CRPITV62Askitis.pdf
PS: In case faster cache-conscious data structured well-suited for strings evolved since
the time the above paper was written, please point me to the papers or example source codes rather.
Someone is implementing it in C++ over on github
https://github.com/chris-vaszauskas/hat-trie
If you need a plain C implementation, this would be a good base to start from.
Java is also fairly readable for a C programmer
http://www.stochasticgeometry.ie/2008/05/06/implementing-hat-tries-in-java/
Please see the HAT-trie implementation site at code.google.com/p/hat-trie for implementation notes and source code.
I know there are many tutorials out there for getting started in C. However Its hard for me to apply the knowledge. The way I've always started out in languages is by writing scripts. Of course C is not a scripting language.
My question isn't so much about learning C as much as it is about how to get started applying C. Great I can write a temperature converter or a text-based rpg. Maybe its because in python I just write up the code in somefile.py and chmod +x somefile.py && somefile.py . I do not really have an equivalent process for C. Every time I read about C its a different compiling process with different flags. Can someone just give me some definite direction on best ways to apply C when you already work with higher-level dynamic scripting languages?
Btw. .. I'm asking about C and not C++.
I usually am on either OpenSuse 11 or Ubuntu 9.04 . "What compiler do i use" is part of the problem. In python there is no choice its just "python somefile.py" same with php or ruby. I didn't know there were choices.
write w.c
#include <stdio.h>
int main(int argc, char *argv[]) {
int i;
for (i = 0; i < argc; ++i) {
printf("Param %d is '%s'\n", i, argv[i]);
}
return 0;
}
and compile with
gcc -Wall -o w w.c
run
./w
As rogeriopvl wrote in a comment, the compilation process is really simple. Just write up the code in somefile.c and
gcc -o somefile somefile.c && ./somefile
(if you're using GCC, and if not, your compiler of choice can probably be invoked similarly) Unless/until you start getting into more complicated projects, it's barely any more complicated than a scripting language. (Well... okay, you may need to link some libraries, once you get beyond the basics. But still, not a huge deal.)
In fact, I did write myself a little shell script that allows me to use C as a scripting language. But the process for setting it up is a little more complicated than what you may want to get into at this stage - it's simpler to just run the compiler each time. Still, if you're interested, I can look up the directions (for Linux) and put them here.
C code needs to be compiled before the program can be run. The exact process is different depending on which platform and compiler you are working on.
For the most part, using an IDE (such as Visual studio, Eclipse, MonoDevelop, and a bunch of others) will do the nasty work for you so that you just have to press a button or click an icon. Download one of these
I asked myself this question when I was learning C. The problem here, if I can say this is a problem, is that C can be used in a broad range of applications and in a broad range of environments, which one with its own IDEs or compilers and libraries. Some examples where you can use C for real staff.
Embedded software. In this case you will probably use some lib.
Network programming (take a look at this book.
Device driver development.
Libraries (both for Linux/Windows and other OSs)
Well this list is endless.
O don't know if I help you with this question. If you give more details about what are you interested in, could be helpful
Good luck
The best advice I can give here is find a topic you're interested in, see if you can make a program to do what you want/assist in doing what you want/adding functionality to the interest of choice, and start coding.
This gives the bonus of doing something you're interested in, and at the same time making something that directly influences it. It should give the motivation to keep steaming onward with the learning process.
I'm working with C a lot at the moment with Linux Kernel modules and am relatively new to C. I've found this rewarding which I think is what's important for this sort of hobby 'temperature converter or a text-based rpg' type programming.
I also struggle finding an application of programming skills. Balance of challenge and reward is important I think.
I have a requirement for porting some existing C code to a IEC 61131-3 compliant PLC.
I have some options of splitting the code into discrete function blocks and weaving those blocks into a standard solution (Ladder, FB, Structured Text etc). But this would require carving up the C code in order to build each function block.
When looking at the IEC spec I realsied that the IEC Instruction List form could be a target language for a compiler. The wikepedia article lists two development tools:
CoDeSys
Beremiz
But these seem to be targeted compiling IEC languages to C, not C to IEC.
Another possible solution is to push the C code through a C to Pascal translator and use that as a starting point for a Structured Text solution.
If not any of these I will go down the route of splitting the code up into function blocks.
Edit
As prompted by mlieson's reply I should have mentioned that the C code is an existing real-time control system. So the programs algorithms should already suit a PLC environment.
Maybe this answer comes too late but it is possible to call C code from CoDeSys thanks to an external library.
You can find documentation on the CoDeSys forum at http://forum-en.3s-software.com/viewtopic.php?t=620
That would give you to use your C code into the PLC with minor modifcations. You'll just have to define the functions or function blocks interfaces.
My guess is that a C to Pascal translator will not get you near enough for being worth the trouble. Structured text looks a lot like Pascal, but there are differences that you will need to fix everywhere.
Not a bug issue, but don't forget that PLCs runtime enviroment is a bit different. A C applications starts at main() and ends when main() returns. A PLC calls it main() over and over again, 100:s of times per second and it never ends.
Usally lengthy calculations and I/O needs to be coded in diffent fashion than a C appliation would use.
Unless your C source is many many thousands lines of code - Rewrite it.
It is impossible. To be short: the IL language is a 4GL (i.e. limited to
the domain, as well as other IEC 61131-3 languages -- ST, FBD, LD, SFC).
The C language is a 3GL.
To understand the problem, try to answer the question, which way to
express in IL manipulations with a pointer? for example, to express call a
function by a pointer. What about interrupts? Low level access to the
peripherial devices?
(really, there are more problems)
BTW, there is the Reflex language, aka "C with processes". Reflex is a 4GL for the
control domain with C-like syntax. But the known translators produce
C-code and Python-code.
If the amount of code to convert is a few thousand lines, recoding by hand is probably your best bet.
If you have lots of code to convert, then an automated tool might be very effective.
Using the DMS Software Reengineering Toolkit we've built translators to map mechanical motion diagrams into RLL (PLC) code. DMS also has full C parser/analyzers/front ends. The pieces are there to build a C to RLL code.
This isn't an easy task. It likely takes 6-12 man-months to configure DMS to something resembling what you want. If that's less than what it takes to do by hand, then its the right way to do it.
There are a few IEC development environments and target hardware that can use C blocks... I would also take a look at the reasons why it HAS to be an IEC-61131 complaint target. I have written extensively on compliance and why it doesn't mean squat.
SOFTplc corp can help I'm sure with user defined loadable modules... and they can be in C..
Schneider also supports C function blocks...
Labview too!! not sure why IEC is important that's all!! the compiler if existed would create bad code for sure:)
Your best bet is to split your C code into smaller parts which can be recoded as PLC functional blocks and use C to PASCAL convertor for each block which you will rewrite in structured text. Prepare to do a lot of manual work since automated conversion will probably disappoint you.
Also take a look at this page: http://www.control.com/thread/1026228786
Every time I've done this, I just parsed and converted it by hand from C directly to ST. I only ran into a few functions that required complete rewrites, although there was very little that dealt with pointers, which is something that ST generally chokes on, unfortunately.
Using the existing C code as blocks that are called by the PLC program would have the added advantage that the C blocks could run at the same periodicity that they did before, and their function is likely already well documented and tested. This would minimize any effect on changes from the existing control system. This is an architecture for controls with software PLCs that I have seen used before.