test_endianness.c File Reference

Program to test the macros in PBI/Endianness.h. More...

#include <stdio.h>
#include <PBI/Endianness.h>

Classes
union	U
	A union used to reference an integer both as a 32 bit integer and as an array of 4 bytes. More...
Defines
#define	ENDIANNESS_NAME_LITTLE   "LITTLE"
	Defines a string describing the endianness of the little endian machines.
#define	ENDIANNESS_NAME_BIG   "BIG"
	Defines a string describing the endianness of the big endian machines.
#define	ENDIANNESS_NAME_UNKNOWN   "UNKNOWN"
	Defines a string when the endianness of the machine cannot be determined.
#define	ENDIANNESS_NAME   ENDIANNESS_NAME_UNKOWN
	Defines a string describing the endianness of the machine.
#define	TEST_MISSION
	Symbol representing the string stating the mission of this test. It is purely here to make the code read nicer.
Functions
int	main (int argc, char **argv)
	Standard main entry point for Unix platforms. It merely calls the testing routine test_endianness ().
int	test_endianness (void)
	The test program itself and also the entry point for running this test on VxWork's platforms.

---

Detailed Description

Program to test the macros in PBI/Endianness.h.

Author:

JJRussell - russell@slac.stanford.edu

   CVS $Id: test_endianness.c,v 1.3 2011/03/24 20:50:58 apw Exp $
  

As with many tests in PBI, the simple ability to correctly compile the test is 90% of proving the test passes.

If this test did not compile correctly the include file PBI/Endianness.h could not determine the endianness of the machine. The only recourse here is to examine the file and see what criteria it is using and why that criteria fails for this machine. Of course, there is the little matter that if the compilation of this test fails, you would not be reading this message.

If PBI/Endianness.h did make a determination, this program can check if that determination is correct by interpreting a 4 byte integer both as an integer and as 4 element character array. On little endian machines the zero'th element of the array will match the low byte of the integer, the next element will match the next lowest byte and so forth. On a big endian machine, the zero'th element of the array will match the high byte of the integer. In this way the endianness determination can be confirmed."

To run the program type

   On Unix platforms: 
   $ test_endianness

   On VxWorks
   > test_endianness ()

  

The program returns 0 if successful, else -1.

---

Define Documentation

#define ENDIANNESS_NAME   ENDIANNESS_NAME_UNKOWN

Defines a string describing the endianness of the machine.

Defines a string describing the endianness of the machine as determined by the macros ins PBI/Endianness.h. This will be one of the previously defined symbols, i.e. ENDIANNESS_NAME_LITTLE, ENDIANNESS_NAME_BIG or ENDIANNESS_NAME_UNKNOWN

Referenced by test_endianness().

---

Function Documentation

int main	(	int	argc,
		char **	argv
	)

Standard main entry point for Unix platforms. It merely calls the testing routine test_endianness ().

Return values:

	0,if	successful
	-1,if	unsuccessful

This program takes no arguments.

References test_endianness().

int test_endianness

(

void

)

The test program itself and also the entry point for running this test on VxWork's platforms.

Return values:

	0,if	successful
	-1,if	unsucceful

References ENDIANNESS, ENDIANNESS_K_BIG, ENDIANNESS_K_LITTLE, ENDIANNESS_K_UNKNOWN, ENDIANNESS_NAME, ENDIANNESS_NAME_BIG, ENDIANNESS_NAME_LITTLE, ENDIANNESS_NAME_UNKNOWN, TEST_MISSION, U::uc, and U::ui.

Referenced by main().