Beginning C user having trouble using #define with functions

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UncleanSpirit

Joined: 04 Nov 2003
Posts: 9

10 May 2006 3:03 Re: Beginning C user having trouble using #define with funct

I'm trying to use a #define pre-processor directive to pass a parameter to a function but the compiler is throwing an error that it expects a numeric argument passed to the function, like a number or C variable that can be evaluated. Here is a portion of my code relevant to the problem issue.

Code:

#define OFF = 0
#define ON = 1

void power_relays( int on_off)
{

// do stuff here

}

void main( void )
{
while ( TRUE )
{
power_relays( OFF );
delay_ms ( 500);
power_relays( ON );
delay_ms ( 500);
}
}

If someone would correct me, I would appreciate it.

Added after 37 minutes:

Never mind. I found my stupid mistake of using "=" with a preprocessor #define.

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semiconductor

Joined: 04 Apr 2003
Posts: 294
Helped: 3
Location: France

10 May 2006 3:19 Re: Beginning C user having trouble using #define with funct

It would be better

Code:

#define OFF 0 //without "="
#define ON 1 //without "="

void power_relays( int on_off)
{

// do stuff here

}

void main( void )
{
while ( TRUE )
{
power_relays( OFF );
delay_ms ( 500);
power_relays( ON );
delay_ms ( 500);
}
}