1 c/c++ compiling @ um/mcsr last modified: september 3, 2008

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C/C++ C/C++ CompilingCompiling

@ UM/MCSR@ UM/MCSR

Last modified: September 3, 2008

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OutlineOutline• Surfing www.mcsr.olemiss.edu website• Logging into the system via ssh• Brief History of C/C++ languages• Basic Structure and Syntax of C/C++ Programs• A quick glance on PICO editor• A detailed look on compilers and compiling

commands• How to run a compiled file• Application of C/C++ Compiling

http://www.mcsr.olemiss.edu/

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Logging into the system Logging into the system using ssh using ssh

• Logging into the system from Windows:– Start the secure shell client:

Start->Programs->SSH Secure Shell->Secure Shell Client – Connect to willow:

From the secure shell window, click Quick Connect. Then, from the Connect to Remote Host pop-up window, enter: Hostname : HostNameUser Name : UserNameClick Connect.

• Logging into the system from Unix:– Start the Terminal:

Finder Utilities Terminal – Type the following command:

ssh UserName@HostNameEnter your password

• If you are a windows user and you want to download ssh:Go to MCSR Web at www.mcsr.olemiss.edu and click on the Software Tab, followed by the Secure Shell link.

• If you are a Unix, Linux, or MAC user, ssh will come with the operating system

http://www.mcsr.olemiss.edu/

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A Brief History of C A Brief History of C languagelanguage

• In the early 1970s, Dennis Ritchie of Bell Laboratories was engaged in a project to develop new operating system. C programming language was then developed.

• In the early 1980's, also at Bell Laboratories, another C++ language was created. This new language was developed by Bjarne Stroustrup and was called C++ which was designed with OOP (Object Oriented Programming) features added to C without significantly changing the C component.

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A Simple C ProgramA Simple C Program/* Take a number multiply it by 10 and display it */

#include <stdio.h>

main(){

int number, result; printf("Type in a number \n");scanf("%d", &number);result = number *10;printf("The number multiplied by 10 equals %d\n", result);

}

Sample Program OutputType in a number23The number multiplied by 10 equals 230

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#include <stdio.h>

main(){


}


Comments are set between /* and */

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#include <stdio.h>

main(){


}


The C pre-processor replaces this directivewith the contents of the stdio.h header file from the standard C library.

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#include <stdio.h>

main(){


}


Every C program must have one main function.

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#include <stdio.h>

main(){


}


Each variable must be explicitly defined as a specific type.

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#include <stdio.h>

main(){


}


The stdio library defines the printf() function for creating output.

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#include <stdio.h>

main(){


}


The stdio library defines the printf() function for creating output.

\n is the newline character

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#include <stdio.h>

main(){


}


The stdio library defines the scanf() function for capturing input.

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#include <stdio.h>

main(){


}


%d tells scanf() to interpret the input as a decimal value

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#include <stdio.h>

main(){


}


The = operator is used for assignment.

The * operator is used for multiplication.

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#include <stdio.h>

main(){


}


%d tells printf() to treat the value of the result variable as a decimal nbr.

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Simple C++ ProgramSimple C++ Program/* Take a number multiply it by 10 and display it */

#include <iostream>

int main(){

int number, result; std::cout<<"Type in a number “<< std::endl;std::cin>>number;result = number *10;std::cout<<"The number multiplied by 10 equals “<<result;

}


C++ pre-processor directives include different versions of the standard library packages.

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#include <iostream>

int main(){

int number, result; std::cout <<"Type in a number “<< std::endl;std::cin >>number;result = number *10;std::cout<<"The number multiplied by 10 equals “<<result;

}


std is an object which you can send messages to—messages such as:

cout, cin, & endl.

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#include <iostream>using namespace std;

int main(){

int number, result; cout <<"Type in a number “ << endl;cin>>number;result = number *10;cout<<"The number multiplied by 10 equals “ <<result;

}


You can use an object’s namespace, to keep from having to specify the name of the object each time you send it a message.

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The PICO EditorThe PICO Editor• General Command

– Write editor contents to a file [Ctrl] o– Save the file and exit pico [Ctrl] x– Spell Check [Ctrl] t– Justify the text [Ctrl] j

• Moving around in your file– Move one character to the right [Ctrl] f or right arrow key– Move one character to the left [Ctrl] b or left arrow key– Move up one line [Ctrl] p or up arrow key– Move down one line [Ctrl] n or down arrow key

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C/C++ source files suffixesC/C++ source files suffixes

• .cpp, .cc, .c suffixes are used for C++ programs that are to be preprocessed, compiled and assembled

• .c for C programs that are to be processed, compiled and assembled

• .h or preprocessor (header) files

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How to run compiled filesHow to run compiled files• The compiling commands create an

executable file known as a.out unless specified otherwise.

• To execute your program, type ./a.out and press Enter.

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Compilation DetailsCompilation Details

object.h

object.cpp

main.cpp

object.s

main.s

object.o

main.o

Output

Source code Assembly Machine Code

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A detailed look into Compilers A detailed look into Compilers and Compiling commandsand Compiling commands

• C/C++ Compilers at UM/MCSR:– Intel C++ Compiler on redwood– MIPS C, MIPSpro C, and MIPSpro C++

version 7.4 compilers on Origin 2800 sweetgum

– Portland Group, GNU, and MPICH Compilers on Beowulf Cluster mimosa

– GNU C Compiler and SUN STUDIO 8 C/C++ Compilers on willow

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Loading the appropriate Intel Loading the appropriate Intel Compiler Module Compiler Module

• Several versions/builds of Intel compilers are available on redwood. To compile, you must first pick which compiler version module you want to load, then load it. Before you can use the module command, you must source the correct setup file for your shell.

– . /usr/share/modules/init/sh (if using ssh) (There should be a space between . and /opt)

• Then you use the module command: – module list (to see if any other versions of compiler modules are loaded) – module purge (to unload any other versions of compiler modules) – module list (to verify that other versions were successfully unloaded) – module avail (to see what versions of compiler modules are available to load)

• For example, to load the latest 10.1 version of the C Compilers: – module load c101– module list

• These are the names of the modules and the compiler versions they correspond to:

– intel-compilers.7.1.037 for c 7.1 – intel-compilers.8.0.042 for c 8.0 – intel-compilers.8.0.046 for c 8.0 – intel-compilers.9.0.027 for c 9.0 – intel-compilers.9.1.046 for c 9.1– intel-compilers.cc.10.1.017 for c 10.1

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Intel C++ Compiler on Intel C++ Compiler on redwoodredwood

• Intel C/C++ Compilers(7.1, 8.0, 9.0, 9.1 & 10.0)– Before using the C/C++ Compiler on redwood,

you must first load the appropriate Intel compiler module.

– Then, to compile:• icc example.c if using the 8.0 or later

compiler• ecc example.c if using the 7.1 compiler.

• With Intel compilers, the invocation syntax is the same regardless of whether your source file is C or C++.

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Exercise 1: Intel Compiler on Exercise 1: Intel Compiler on RedwoodRedwood

1. If you have an account on redwood, login to it. 2. Copy the two example source files from /usr/local/examples/c to your

working directory:A. cd 1 (if using a common class account, cd to your numbered subdirectory)B. cp /usr/local/examples/c/hello.c ./hello.cC. cp /usr/local/examples/c/addtwo.cpp ./addtwo.cpp

3. Source the appropriate modules environment script for your shell:C. . /usr/share/modules/init/bash

4. Use “module avail” to see which modules are available5. Load one of the 10.X modules

A. module load c101B. module list

6. Compile/execute the hello.c and addtwo.cppA. icc hello.cB. ./a.outC. icc addtwo.cppD. ./a.out

7. Clear all loaded modulesA. module listB. module clearC. module list

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SweetgumSweetgum and and MimosaMimosa

• Sweetgum: MIPSPro 7.4 Compilers, version 7.4– To compile with cc/CC on sweetgum, enter:

• CC example.c

– To find out more about compilers, enter:• man cc OR man CC

• Mimosa: PGI CDK 7.2 Compilers– To compile with the C/C++ compilers, enter:

• /usr/local/apps/pgi-7.2/linux86/7.2/bin/pgCC example.c

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GNU C Compiler and GNU C Compiler and SUN STUDIO SUN STUDIO 8 C/C++ Compilers8 C/C++ Compilers on on willowwillow

• gcc file1.c command is used to compile and link a C program on willow

• g++ file1.c command is used to compile and link a C++ program on willow

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Willow & Common Compiler Willow & Common Compiler FlagsFlags

• Sun Studio C/C++ Compilers, Version 5.5:– To compile with C/C++, enter:

• cc example.c (C)• CC example.c (C++)

– Compilers located in /ptmp/studio8/SUNWspro/bin

• GNU C/C++ Compilers, Version 3.3.2– To compile with C/C++, enter:

• gcc example.c (C)• g++ example.c (C++)

– Compilers located in /usr/local/bin

• Use which to see which compiler version is being found.– which cc– which CC

• If there are no compilation errors this creates an executable file called a.out. To execute the C/C++ program, enter: ./a.out.

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Exercise 2: Compile C/C++ on Exercise 2: Compile C/C++ on willowwillow

1. Log in to willow using the account: student2. Change to your numbered working directory:

– cd 1

3. Compile/execute hello.c using GNU C compiler– gcc hello.c– ./a.out

4. Compile/execute simpleB.cpp using Sun’s C++ – CC simpleB.cpp– ./a.out

5. Try to compile hello.c using Sun’s C compiler– cc hello.c

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Example C/C++ Flags Example C/C++ Flags cc <flag> <filename.c>

-c Compile or assemble the source files, but do not link.

-S Stop after the stage of compilation proper

-E Stop after the preprocessing stage

-o newFilename Name executable something besides a.out

-V Show the compiler version (SUN)-v Show the compiler version (GNU)

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Exercise 3: Compiler OptionsExercise 3: Compiler Options

1. Compile/execute hello.c using GNU C compiler, and name the executable file helloc.exe

– gcc hello.c –o helloc.exe– ./helloc.exe

2. Determine what version of the GNU compilers are installed

– gcc -v– g++ -v

3. Determine version of installed Sun’s compiler– CC –V

– /ptmp/studio8/SUNWspro/bin/cc -V

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Frequently Asked ?’s on C/C++ Frequently Asked ?’s on C/C++ WillowWillow

1. How can I compile one or more C/C++ source files into object files without yet linking into an executable program?

2. How can I ensure the compiler will find a C/C++ header file referenced by my program?

3. How can I ensure the compiler will find a pre-compiled module referenced by my program but residing in a system- or user-defined archive library?

4. How can I add my own module to a library archive for others on the system to re-use?

Answers here (or in Advanced C/C++ Compiling Unix Camp)http://www.mcsr.olemiss.edu/appssubpage.php?pagename=cwillow.inc

1 c/c++ compiling @ um/mcsr last modified: september 3, 2008

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