bool _stdcall X9241Write(unsigned char address,
  unsigned char instruction)
{
  if (
   I2CStart() &&
   I2CTransmit(fullAddr) &&
   I2CGetAck() &&
   I2CTransmit(instruction) &&
   I2CGetAck() &&
   I2CStop()
  )
   return TRUE;
  else
   return FALSE;
}


Date sent:              Wed, 11 Apr 2001 09:41:44 +0100
Send reply to:          pic microcontroller discussion list <PICLIST@MITVMA.MIT.EDU>
From:                   Michael Rigby-Jones <mrjones@NORTELNETWORKS.COM>
Subject:                [OT]: Coding style
To:                     PICLIST@MITVMA.MIT.EDU

> This is a plea for some advice on coding style from any of the experts
> on the list.  I have written some I2C drivers for use under Windows
> for a project, and whilst they are perfectly functional I feel that my
> coding style could definately be improved.  Now, a function should
> preferably have one entry and one exit.  However my code looks
> something like the function below.  Here I am calling several
> functions that return a boolean to indicate success or failure, and I
> want to exit the calling function if a failure is returned.
>
>
> bool _stdcall X9241Write(unsigned char address, unsigned char
> instruction) { /* Function:               X9241Write Arguments:
> address = slave address of device, instruction = instruction byte to
> send to pot Return:                 True if success, false if fail.
> Description:    Generic write command for instructions that required
> no additional data. */
>
>         unsigned char fullAddr;
>
>     fullAddr = (unsigned char)(X9241_ADDR | (address & 0x0F));
>
>     if(!I2CStart())
>         return false;
>
>     // send slave address
>     if(!I2CTransmit(fullAddr))
>         return false;
>
>     if(!I2CGetAck())
>         return false;
>
>         // send the MSB
>     if(!I2CTransmit(instruction))
>         return false;
>
>     if(!I2CGetAck())
>         return false;
>
>     if(!I2CStop())
>         return false;
>
>     return true;
> }
>
> Now I could nest all the if() statements, but to my mind this would
> become far more confusing than the above, especially with some of the
> longer functions.  Or perhaps set a local variable and check it before
> calling each sub function i.e.
>
> bool success;
>
> success = I2CStart();
>
> if(success)
>         success = I2CTransmit(fullAddr);
> if(success)
>         success = I2CGetAck();
>
> etc, etc...
>
> This would work and I could use one return at the end, but to my mind
> a failure at the top of the function causes unnecessary overhead in in
> checking the success variable multiple times to reach the end of the
> function. I could use a goto and a label at the end of the function,
> but that seems infinitely worse than multiple returns.
>
> Any other suggestions?
>
> Regards
>
> Mike
>
> --
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> mailto:piclist-unsubscribe-request@mitvma.mit.edu
>


==============================
Ruben Jvnsson
AB Liros Elektronik
Box 9124, 200 39 Malmv, Sweden
TEL INT +46 40142078
FAX INT +46 40947388
ruben@pp.sbbs.se
==============================

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