The Book of C Release 2018.01
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What Are the Problems with Embedded Linux?
What Are the Problems with Embedded Linux? Every Operating System Has Benefits and Drawbacks Linux is ubiquitous. It runs most internet servers, is inside Android* smartphones, and is used on millions of embedded systems that, in the past, ran Real-Time Operating Systems (RTOSes). Linux can (and should) be used were possible for embedded projects, but while it gives you extreme choice, it also presents the risk of extreme complexity. What, then, are the trade-offs between embedded Linux and an RTOS? In this article, we cover some key considerations when evaluating Linux for a new development: ■ Design your system architecture first ■ What is Linux? ■ Linux vs. RTOSes ■ Free software is about liberty—not price ■ How much does Embedded Linux cost? ■ Why pay for Embedded Linux? ■ Should you buy Embedded Linux or roll-your-own (RYO)? ■ To fork or not to fork? ■ Software patching ■ Open source licensing ■ Making an informed decision The important thing is not whether Linux or an RTOS is “the best,” but whether either operating system—or both together—makes the most technical and financial sense for your project. We hope this article helps you make an informed decision. Design Your System Architecture First It is important to design your system architecture first—before choosing either Linux or an RTOS—because both choices can limit architectural freedom. You may discover that aspects of your design require neither Linux nor an RTOS, making your design a strong candidate for a heterogeneous approach that includes one or more bare-metal environments (with possibly a Linux and/or RTOS environment as well). -
C-Style Strings
Introduction to printf and scanf A conceptual model of a C-string String handling functions in the C standard library String parsing functions Stuff to learn on your own C-Style Strings Mike Closson Dept of Computing Science University of Alberta Small modifications: Michael Buro Feb.2006 22nd February 2006 Mike Closson C-Style Strings Introduction to printf and scanf A conceptual model of a C-string String handling functions in the C standard library String parsing functions Stuff to learn on your own Introduction to printf, fprintf. Printing Strings: /* Print to standard output */ printf( "Hello, World!\n" ); /* Print to file associated with filepointer fp */ fprintf( fp, "Hello, World!\n" ); Mike Closson C-Style Strings Introduction to printf and scanf A conceptual model of a C-string String handling functions in the C standard library String parsing functions Stuff to learn on your own Flushing an I/O stream with fflush. For performance reasons, data written with the stream functions (fwrite, printf, fprintf) may not always appear on the terminal or file after the printf function returns. To force the data to be written, use the fflush function. printf("Enter your password: "); fflush( stdout ); Usually, fflush is not needed. Mike Closson C-Style Strings Introduction to printf and scanf A conceptual model of a C-string String handling functions in the C standard library String parsing functions Stuff to learn on your own Reading data with scanf. Data is written with printf, and data is read with scanf. char password[100]; printf( "Enter your password: " ); fflush( stdout ); if (scanf( "%99s", password ) != 1) // Error .. -
User's Manual
rBOX610 Linux Software User’s Manual Disclaimers This manual has been carefully checked and believed to contain accurate information. Axiomtek Co., Ltd. assumes no responsibility for any infringements of patents or any third party’s rights, and any liability arising from such use. Axiomtek does not warrant or assume any legal liability or responsibility for the accuracy, completeness or usefulness of any information in this document. Axiomtek does not make any commitment to update the information in this manual. Axiomtek reserves the right to change or revise this document and/or product at any time without notice. No part of this document may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without the prior written permission of Axiomtek Co., Ltd. Trademarks Acknowledgments Axiomtek is a trademark of Axiomtek Co., Ltd. ® Windows is a trademark of Microsoft Corporation. Other brand names and trademarks are the properties and registered brands of their respective owners. Copyright 2014 Axiomtek Co., Ltd. All Rights Reserved February 2014, Version A2 Printed in Taiwan ii Table of Contents Disclaimers ..................................................................................................... ii Chapter 1 Introduction ............................................. 1 1.1 Specifications ...................................................................................... 2 Chapter 2 Getting Started ...................................... -
Cheat Sheets of the C Standard Library
Cheat Sheets of the C standard library Version 1.06 Last updated: 2012-11-28 About This document is a set of quick reference sheets (or ‘cheat sheets’) of the ANSI C standard library. It contains function and macro declarations in every header of the library, as well as notes about their usage. This document covers C++, but does not cover the C99 or C11 standard. A few non-ANSI-standard functions, if they are interesting enough, are also included. Style used in this document Function names, prototypes and their parameters are in monospace. Remarks of functions and parameters are marked italic and enclosed in ‘/*’ and ‘*/’ like C comments. Data types, whether they are built-in types or provided by the C standard library, are also marked in monospace. Types of parameters and return types are in bold. Type modifiers, like ‘const’ and ‘unsigned’, have smaller font sizes in order to save space. Macro constants are marked using proportional typeface, uppercase, and no italics, LIKE_THIS_ONE. One exception is L_tmpnum, which is the constant that uses lowercase letters. Example: int system ( const char * command ); /* system: The value returned depends on the running environment. Usually 0 when executing successfully. If command == NULL, system returns whether the command processor exists (0 if not). */ License Copyright © 2011 Kang-Che “Explorer” Sung (宋岡哲 <explorer09 @ gmail.com>) This work is licensed under the Creative Commons Attribution 3.0 Unported License. http://creativecommons.org/licenses/by/3.0/ . When copying and distributing this document, I advise you to keep this notice and the references section below with your copies, as a way to acknowledging all the sources I referenced. -
Confine: Automated System Call Policy Generation for Container
Confine: Automated System Call Policy Generation for Container Attack Surface Reduction Seyedhamed Ghavamnia Tapti Palit Azzedine Benameur Stony Brook University Stony Brook University Cloudhawk.io Michalis Polychronakis Stony Brook University Abstract The performance gains of containers, however, come to the Reducing the attack surface of the OS kernel is a promising expense of weaker isolation compared to VMs. Isolation be- defense-in-depth approach for mitigating the fragile isola- tween containers running on the same host is enforced purely in tion guarantees of container environments. In contrast to software by the underlying OS kernel. Therefore, adversaries hypervisor-based systems, malicious containers can exploit who have access to a container on a third-party host can exploit vulnerabilities in the underlying kernel to fully compromise kernel vulnerabilities to escalate their privileges and fully com- the host and all other containers running on it. Previous con- promise the host (and all the other containers running on it). tainer attack surface reduction efforts have relied on dynamic The trusted computing base in container environments analysis and training using realistic workloads to limit the essentially comprises the entire kernel, and thus all its set of system calls exposed to containers. These approaches, entry points become part of the attack surface exposed to however, do not capture exhaustively all the code that can potentially malicious containers. Despite the use of strict potentially be needed by future workloads or rare runtime software isolation mechanisms provided by the OS, such as conditions, and are thus not appropriate as a generic solution. capabilities [1] and namespaces [18], a malicious tenant can Aiming to provide a practical solution for the protection leverage kernel vulnerabilities to bypass them. -
LTIB Quick Start: Targeting the Coldfire Mcf54418tower Board By: Soledad Godinez and Jaime Hueso Guadalajara Mexico
Freescale Semiconductor Document Number: AN4426 Application Note Rev. 0, December 2011 LTIB Quick Start: Targeting the ColdFire MCF54418Tower Board by: Soledad Godinez and Jaime Hueso Guadalajara Mexico Contents 1 Introduction 1 Introduction................................................................1 The purpose of this document is to indicate step-by-step how 2 LTIB..........................................................................1 to accomplish these tasks: • Install the BSP on a host development system. 2.1 Introduction....................................................1 • Run Linux Target Image Builder (LTIB) to build target 2.2 Installing the BSP...........................................2 images. • Boot Linux on the ColdFire MCF54418 Tower board. 2.3 Running LTIB................................................7 3 Target deployment .................................................13 This document is a guide for people who want to properly set up the Freescale Linux Target Image Builder (LTIB) for the 3.1 The Tower kit ..............................................13 ColdFire MCF54418 Tower Board Support Package (BSP). 3.2 Constructing the Tower kit...........................15 3.3 Programming U-boot, kernel, and root file system.............................................16 2 LTIB 3.4 Configuring U-boot......................................24 3.5 Running.......................................................25 4 Conclusions.............................................................26 2.1 Introduction Freescale GNU/Linux -
A Type-Checking Preprocessor for Cilk 2, a Multithreaded C Language
A Typechecking Prepro cessor for Cilk a Multithreaded C Language by Rob ert C Miller Submitted to the Department of Electrical Engineering and Computer Science in partial fulllment of the requirements for the degrees of Bachelor of Science in Computer Science and Engineering and Master of Engineering in Electrical Engineering and Computer Science at the Massachusetts Institute of Technology May Copyright Massachusetts Institute of Technology All rights reserved Author ::::::::::::::::::::::::::::::::::::::::::::::::::: :::::::::::::::::::::::: Department of Electrical Engineering and Computer Science May Certied by ::::::::::::::::::::::::::::::::::::::::::::::::::: ::::::::::::::::::: Charles E Leiserson Thesis Sup ervisor Accepted by ::::::::::::::::::::::::::::::::::::::::::::::::::: ::::::::::::::::::: F R Morgenthaler Chairman Department Committee on Graduate Theses A Typechecking Prepro cessor for Cilk a Multithreaded C Language by Rob ert C Miller Submitted to the Department of Electrical Engineering and Computer Science on May in partial fulllment of the requirements for the degrees of Bachelor of Science in Computer Science and Engineering and Master of Engineering in Electrical Engineering and Computer Science Abstract This thesis describ es the typechecking optimizing translator that translates Cilk a C ex tension language for multithreaded parallel programming into C The CilktoC translator is based on CtoC a to ol I developed that parses type checks analyzes and regenerates a C program With a translator based on CtoC -
N2429 V 1 Function Failure Annotation
ISO/IEC JTC 1/SC 22/WG14 N2429 September 23, 2019 v 1 Function failure annotation Niall Douglas Jens Gustedt ned Productions Ltd, Ireland INRIA & ICube, Université de Strasbourg, France We have been seeing an evolution in proposals for the best syntax for describing how to mark how a function fails, such that compilers and linkers can much better optimise function calls than at present. These papers were spurred by [WG21 P0709] Zero-overhead deterministic exceptions, which proposes deterministic exception handling for C++, whose implementation could be very compatible with C code. P0709 resulted in [WG21 P1095] Zero overhead deterministic failure – A unified mecha- nism for C and C++ which proposed a C syntax and exception-like mechanism for supporting C++ deterministic exceptions. That was responded to by [WG14 N2361] Out-of-band bit for exceptional return and errno replacement which proposed an even wider reform, whereby the most popular idioms for function failure in C code would each gain direct calling convention support in the compiler. This paper synthesises all of the proposals above into common proposal, and does not duplicate some of the detail in the above papers for brevity and clarity. It hews closely to what [WG14 N2361] proposes, but with different syntax, and in addition it shows how the corresponding C++ features can be constructed on top of it, without loosing call compatibility with C. Contents 1 Introduction 2 1.1 Differences between WG14 N2361 and WG21 P1095 . .3 2 Proposed Design 4 2.1 errno-related function failure editions . .5 2.2 When to choose which edition . -
C Programming
C PROGRAMMING 6996 Columbia Gateway Drive Suite 100 Columbia, MD 21046 Tel: 443-692-6600 http://www.umbctraining.com C PROGRAMMING Course # TCPRG3000 Rev. 10/14/2016 ©2016 UMBC Training Centers 1 C PROGRAMMING This Page Intentionally Left Blank ©2016 UMBC Training Centers 2 C PROGRAMMING Course Objectives ● At the conclusion of this course, students will be able to: ⏵ Write non-trivial C programs. ⏵ Use data types appropriate to specific programming problems. ⏵ Utilize the modular features of the C languages. ⏵ Demonstrate efficiency and readability. ⏵ Use the various control flow constructs. ⏵ Create and traverse arrays. ⏵ Utilize pointers to efficiently solve problems. ⏵ Create and use structures to implement new data types. ⏵ Use functions from the C runtime library. ©2016 UMBC Training Centers 3 C PROGRAMMING This Page Intentionally Left Blank ©2016 UMBC Training Centers 4 C PROGRAMMING Table of Contents Chapter 1: Getting Started..............................................................................................9 What is C?..................................................................................................................10 Sample Program.........................................................................................................11 Components of a C Program......................................................................................13 Data Types.................................................................................................................14 Variables.....................................................................................................................16 -
C Programming Tutorial
C Programming Tutorial C PROGRAMMING TUTORIAL Simply Easy Learning by tutorialspoint.com tutorialspoint.com i COPYRIGHT & DISCLAIMER NOTICE All the content and graphics on this tutorial are the property of tutorialspoint.com. Any content from tutorialspoint.com or this tutorial may not be redistributed or reproduced in any way, shape, or form without the written permission of tutorialspoint.com. Failure to do so is a violation of copyright laws. This tutorial may contain inaccuracies or errors and tutorialspoint provides no guarantee regarding the accuracy of the site or its contents including this tutorial. If you discover that the tutorialspoint.com site or this tutorial content contains some errors, please contact us at [email protected] ii Table of Contents C Language Overview .............................................................. 1 Facts about C ............................................................................................... 1 Why to use C ? ............................................................................................. 2 C Programs .................................................................................................. 2 C Environment Setup ............................................................... 3 Text Editor ................................................................................................... 3 The C Compiler ............................................................................................ 3 Installation on Unix/Linux ............................................................................ -
Choosing System C Library
Choosing System C library Khem Raj Comcast Embedded Linux Conference Europe 2014 Düsseldorf Germany Introduction “God defined C standard library everything else is creation of man” Introduction • Standard library for C language • Provides primitives for OS service • Hosted/freestanding • String manipulations • Types • I/O • Memory • APIs Linux Implementations • GNU C library (glibc) • uClibc • eglibc – Now merged into glibc • Dietlibc • Klibc • Musl • bionic Multiple C library FAQs • Can I have multiple C libraries side by side ? • Can programs compiled with glibc run on uclibc or vice versa ? • Are they functional compatible ? • Do I need to choose one over other if I am doing real time Linux? • I have a baremetal application what libc options do I have ? Posix Compliance • Posix specifies more than ISO C • Varying degree of compliance What matters to you ? • Code Size • Functionality • Interoperability • Licensing • Backward Compatibility • Variety of architecture support • Dynamic Linking • Build system Codesize • Dietlibc/klibc – Used in really small setup e.g. initramfs • Bionic – Small linked into every process • uClibc – Configurable • Size can be really small at the expense of functionality • Eglibc – Has option groups can be ( < 1M ) License • Bionic – BSD/Apache-2.0 • Musl - MIT • Uclibc – LGPL-2.1 • Eglibc/Glibc – LGPL-2.1 Assigned to FSF • Dietlibc – GPLv2 • Klibc – GPLv2 • Newlib – some parts are GPLv3 Compliance • Musl strives for ISO/C and POSIX compliance No-mmu • uClibc supported No-mmu Distributions • Glibc is used in -
The C-- Language Reference Manual
The C-- Language Reference Manual Simon Peyton Jones Thomas Nordin Dino Oliva Pablo Nogueira Iglesias April 23, 1998 Contents 1 Introduction 3 2 Syntax definition 3 2.1 General ......................................... 3 2.2 Comments........................................ 6 2.3 Names.......................................... 6 2.4 Namescope....................................... 6 2.5 The import and export declarations ........................ 6 2.6 Constants ....................................... 7 2.6.1 Integer and floating point numbers . ...... 7 2.6.2 Characters and strings . ... 7 3 Fundamental concepts in C-- 7 3.1 Memory......................................... 7 3.2 Datasegment ..................................... 8 3.3 Codesegment..................................... 8 3.4 Types .......................................... 8 3.5 Local variables (or registers) . ......... 8 3.6 Addresses ....................................... 9 3.7 Names.......................................... 9 3.8 Foreign language interface . ....... 9 4 Data layout directives 9 4.1 Labels.......................................... 10 4.2 Initialisation.................................. ..... 10 4.3 Alignment....................................... 12 1 5 Procedures 12 5.1 Proceduredefinition..... ...... ..... ...... ...... .. ..... 12 5.2 Statements...................................... 13 5.2.1 skip; ..................................... 13 5.2.2 Declaration ................................... 13 5.2.3 Assignment................................... 13 5.2.4