Symbian -Platform vs UNIX

Hello World

Assuming -that the user is new to the UNIX environment, writing a simple program that -displays a string on a console does not take more than a day’s effort. Its -simply 4-5 lines of code as shown below:

#include <stdio.h> -int main(int argc, char** argv) - { - printf(“Hello world\n”); - return 0; - }

The code contains a main() , one printf statement, -and one #include< >. By convention UNIX applications will -map descriptor 0 with standard input (STDIN), descriptor -1 with standard output (STDOUT), and descriptor 2 with standard -error (STDERROR) of the process. So, there is no need to -create/open standard input/output/error for a process before using them. Notice -also that, main() takes two arguments. These arguments will -be read from the command prompt before invoking main() and -will be passed to main. These arguments are not mandatory; they can be ignored. -No additional work is needed for having these arguments.

If the user -attempts to display a string on a console using Symbian platform, a lot of -effort goes into collecting the materials, and for coding. The first time -the developer may find the code a little complex to understand.

#include <e32std.h> -#include <e32cons.h> -int HelloWorldL() - { - CConsoleBase* console = Console::NewL(_L("Hello World"), TSize( KConsFullScreen, KConsFullScreen)); - console->Printf(_L(“Hello World\n”)); - delete console; - return 0; - } - -TInt E32Main() - { - __UHEAP_MARK; - CTrapCleanup* cleanup = CTrapCleanup::New(); - TInt retVal = KErrNone; - if (cleanup) - { - TRAP(retVal, HelloWorldL()); - __ASSERT_ALWAYS(!retVal, User::Panic(_L("Hello-World PANIC"), retVal)); - //Destroy cleanup stack - delete cleanup; - } - __UHEAP_MARKEND; - return retVal; - } -

The code above has some header inclusions, two functions, and -some complicated codes. In Symbian platform, the entry function for an EXE -is E32Main (not main as in UNIX). The following actions are -done to print a message on a console:

Mark the heap using __UHEAP_MARK (not -mandatory).
Create the cleanup stack. -Have a top-level TRAP for the function HelloWorldL() function.
In the HelloWorldL() function, -create a console object.
Do print on the created -console object.
Delete the console.
Delete the cleanup stack.
Unmark the heap (not -mandatory if the heap is not marked).

In Symbian platform, a console is not created by default; it has to -be created explicitly. Symbian platform does not give a rich set of APIs needed -to perform I/O operations on a console. The I/O operations that can be performed -on a console in Symbian platform are limited to:

printing strings and reading one character at a time
getting cursor position

In case the user is interested in command line arguments, it takes -some more additional work. The user must read explicitly from the command -prompt by using the APIs provided by Symbian platform.

File I/O

This -section compares the ease of programming in the P.I.P.S. environment against -programming on Symbian platform.

/* File I/O in UNIX environment */ - FILE* fp = fopen(“file.txt”, w); - if (fp) { - fprintf(fp, “Write some data”); - fclose(); - } -//File I/O in Symbian platform - RFs fSession; - User::LeaveIfError(fSession.Connect()); - RFile file; - ret = file.Open(fSession, _L(“file.txt”), EFileWrite); - if (ret) - { - ret = file.Create(fSession, _L(“file.txt”), EFileWrite); - } - if (!ret) - { - file.Write(_L8(“Write some data”)); - } - file.Close(); - fSession.Close(); -

The example above shows the complexity of the code in Symbian -platform for doing simple file I/O. In addition to coding complexity, the -user must include and link with:

efsrv.lib for any file-related operation
esock.lib for network-related operation
commdb.lib for selecting IAPs

Since most of the resources under Symbian platform are accessed through -client/server IPC, the user must connect with the corresponding server before -doing any operation and close the session on completion of the operation. -For example:

connect with the file server before file operations
connect with the socket server for socket-related operation
connect to the communication server before serial communication operation

P.I.P.S. eliminates all these operations. P.I.P.S. allows the -user to code, as if it were done for the UNIX or Linux environment and lets -the user link the application with P.I.P.S..

Thread creation

This -section deals with thread creation in the UNIX and Symbian platform environments.

/* Thread creation in UNIX environment*/ - void* ThreadEntryPoint( void* aParam ); - int exitReason = 0; - int retVal = 0; - pthread_t threadID = 0; - pthread_attr_t threadAttr; - pthread_attr_init(&threadAttr); - retVal = pthread_create(&threadID, &threadAttr, ThreadEntryPoint, (void*)NULL ); - if(retVal == 0) { - retVal = pthread_join(threadID1, (void**)&exitReason); - } -// Thread creation in Symbian OS - TInt ThreadEntryPoint( TAny* aData ); - … - RThread thread; - thread.Create(_L("MY-THREAD"), ThreadEntryPoint, 4096, NULL, NULL); - TRequestStatus stat; - thread.Logon(stat); - //Start executing the thread. - thread.Resume(); - //Wait for the thread to die. - User::WaitForRequest(stat); - exitReason = thread.ExitReason(); - thread.Close(); -

In addition the difference in the code for creating threads -using pthread_create and RThread::Create(), -a thread created using RThread::Create() also expects the ThreadEntryPoint() function -to create its own vcleanup stack and a top-level TRAP, if required. Else, -the thread may crash or panic. But this does not have to be done for a thread -created using pthread_create. pthread_create does that for -the developer.

+ + + + + +Symbian +Platform vs UNIX +

Hello World

Assuming +that the user is new to the UNIX environment, writing a simple program that +displays a string on a console does not take more than a day’s effort. Its +simply 4-5 lines of code as shown below:

#include <stdio.h> +int main(int argc, char** argv) + { + printf(“Hello world\n”); + return 0; + }

The code contains a main() , one printf statement, +and one #include< >. By convention UNIX applications will +map descriptor 0 with standard input (STDIN), descriptor +1 with standard output (STDOUT), and descriptor 2 with standard +error (STDERROR) of the process. So, there is no need to +create/open standard input/output/error for a process before using them. Notice +also that, main() takes two arguments. These arguments will +be read from the command prompt before invoking main() and +will be passed to main. These arguments are not mandatory; they can be ignored. +No additional work is needed for having these arguments.

If the user +attempts to display a string on a console using Symbian platform, a lot of +effort goes into collecting the materials, and for coding. The first time +the developer may find the code a little complex to understand.

#include <e32std.h> +#include <e32cons.h> +int HelloWorldL() + { + CConsoleBase* console = Console::NewL(_L("Hello World"), TSize( KConsFullScreen, KConsFullScreen)); + console->Printf(_L(“Hello World\n”)); + delete console; + return 0; + } + +TInt E32Main() + { + __UHEAP_MARK; + CTrapCleanup* cleanup = CTrapCleanup::New(); + TInt retVal = KErrNone; + if (cleanup) + { + TRAP(retVal, HelloWorldL()); + __ASSERT_ALWAYS(!retVal, User::Panic(_L("Hello-World PANIC"), retVal)); + //Destroy cleanup stack + delete cleanup; + } + __UHEAP_MARKEND; + return retVal; + } +

The code above has some header inclusions, two functions, and +some complicated codes. In Symbian platform, the entry function for an EXE +is E32Main (not main as in UNIX). The following actions are +done to print a message on a console:

Mark the heap using __UHEAP_MARK (not +mandatory).
Create the cleanup stack. +Have a top-level TRAP for the function HelloWorldL() function.
In the HelloWorldL() function, +create a console object.
Do print on the created +console object.
Delete the console.
Delete the cleanup stack.
Unmark the heap (not +mandatory if the heap is not marked).

In Symbian platform, a console is not created by default; it has to +be created explicitly. Symbian platform does not give a rich set of APIs needed +to perform I/O operations on a console. The I/O operations that can be performed +on a console in Symbian platform are limited to:

printing strings and reading one character at a time
getting cursor position

In case the user is interested in command line arguments, it takes +some more additional work. The user must read explicitly from the command +prompt by using the APIs provided by Symbian platform.

File I/O

This +section compares the ease of programming in the P.I.P.S. environment against +programming on Symbian platform.

/* File I/O in UNIX environment */ + FILE* fp = fopen(“file.txt”, w); + if (fp) { + fprintf(fp, “Write some data”); + fclose(); + } +//File I/O in Symbian platform + RFs fSession; + User::LeaveIfError(fSession.Connect()); + RFile file; + ret = file.Open(fSession, _L(“file.txt”), EFileWrite); + if (ret) + { + ret = file.Create(fSession, _L(“file.txt”), EFileWrite); + } + if (!ret) + { + file.Write(_L8(“Write some data”)); + } + file.Close(); + fSession.Close(); +

The example above shows the complexity of the code in Symbian +platform for doing simple file I/O. In addition to coding complexity, the +user must include and link with:

efsrv.lib for any file-related operation
esock.lib for network-related operation
commdb.lib for selecting IAPs

Since most of the resources under Symbian platform are accessed through +client/server IPC, the user must connect with the corresponding server before +doing any operation and close the session on completion of the operation. +For example:

connect with the file server before file operations
connect with the socket server for socket-related operation
connect to the communication server before serial communication operation

P.I.P.S. eliminates all these operations. P.I.P.S. allows the +user to code, as if it were done for the UNIX or Linux environment and lets +the user link the application with P.I.P.S.

Thread creation

This +section deals with thread creation in the UNIX and Symbian platform environments.

/* Thread creation in UNIX environment*/ + void* ThreadEntryPoint( void* aParam ); + int exitReason = 0; + int retVal = 0; + pthread_t threadID = 0; + pthread_attr_t threadAttr; + pthread_attr_init(&threadAttr); + retVal = pthread_create(&threadID, &threadAttr, ThreadEntryPoint, (void*)NULL ); + if(retVal == 0) { + retVal = pthread_join(threadID1, (void**)&exitReason); + } +// Thread creation in Symbian Platform + TInt ThreadEntryPoint( TAny* aData ); + … + RThread thread; + thread.Create(_L("MY-THREAD"), ThreadEntryPoint, 4096, NULL, NULL); + TRequestStatus stat; + thread.Logon(stat); + //Start executing the thread. + thread.Resume(); + //Wait for the thread to die. + User::WaitForRequest(stat); + exitReason = thread.ExitReason(); + thread.Close(); +

In addition the difference in the code for creating threads +using pthread_create and RThread::Create(), +a thread created using RThread::Create() also expects the ThreadEntryPoint() function +to create its own vcleanup stack and a top-level TRAP, if required. Else, +the thread may crash or panic. But this does not have to be done for a thread +created using pthread_create. pthread_create does that for +the developer.

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