Technical Note 	: SLE0006

Author	: Scott Evans

Created/Modified	: 11/9/98

Description	: Useful compiler symbols

This technical note describes some of the GNU compiler symbols which can
be used in your C programs.

All the symbols have the following format __SYMBOL__.

Time and date

There are two compiler symbols which return a string containing the time
and date when the source file was compiled. They are __DATE__ and
__TIME__. These can be used to time stamp your code.

The following example will display the build time of the program.

Example

printf(“Build time : %s %s\n”,__DATE__,__TIME__);

Function names

The symbol __FUNCTION__ can be used to return the string containing the
name of the current function. This can be useful when printing errors.
Following is an example.

#define PrintStatus(s) 

	printf(“%s : %s”,__FUNCTION__,s)

int InitSoundData(SOUND_EFFECT *se,u_byte *vh,u_byte *vb)

{

 	word vabid;

    

   	 // Transfer sound data, wait for data to be transfered

    

    	vabid=SsVabTransfer(vh,vb,-1,SS_WAIT_COMPLETED);

	if(vabid<0)

		PrintStatus(“Failed\n”);

	Else

		PrintStatus(“Completed\n”);

	Return(vabid);

}

So if vabid is less than 0 the following will be output.

InitSoundData : Failed

Otherwise the output will be

InitSoundData : Completed

GNU compiler

The symbol __GNUC__ is defined when you are using GNU C. The symbol
__STDC__ is defined when using standard C.

These can be useful if you are using GNU extensions to C.

Including data

You can include binary data in C source files with the following method.

u_byte binary_data[]={

	#include “binary.dat”

};

This is basically equivalent to the following assembly language code
except the contents of binary.dat needs to be in the following format.

0x100,0x200,0x300,0x400 etc..

I use a very simple program to convert binary files into this format.

			global binary_data

binary_data:	incbin “binary.dat”

Make note that large files will slow down the compiler.