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Sun Studio 12: C++ User's Guide

A.2.147.1 Values

The following table lists the alignment and behavior values for -xmemalign

Table A–39 The -xmemalign Alignment and Behavior Values

a

 

b

 

1 

Assume at most 1 byte alignment. 

i 

Interpret access and continue execution. 

2 

Assume at most 2 byte alignment. 

s 

Raise signal SIGBUS. 

4 

Assume at most 4 byte alignment. 

f 

For variants of -xarch=v9 only:

Raise signal SIGBUS for alignments less or equal to 4,otherwise interpret access and continue execution. For all other -xarch values, the f flag is equivalent to i.

8 

Assume at most 8 byte alignment. 

   

16 

Assume at most 16 byte alignment 

   

You must specify -xmemalign whenever you want to link to an object file that was compiled with the value of b set to either i or f. For a complete list of all compiler options that must be specified at both compile time and at link time, see 3.3.3 Compile-Time and Link-Time Options.

Defaults

The following default values only apply when no -xmemalign option is present:

Here is the default when the -xmemalign option is present but no value is given:

Examples

The following table shows how you can use -xmemalign to handle different alignment situations.

Table A–40 Examples of -xmemalign

Command 

Situation  

-xmemalign=1s

There are many misaligned accesses so trap handling is too slow. 

-xmemalign=8i

There are occasional, intentional, misaligned accesses in code that is otherwise correct. 

-xmemalign=8s

There should be no misaligned accesses in the program. 

-xmemalin=2s

You want to check for possible odd-byte accesses. 

-xmemalign=2i

You want to check for possible odd-byte access and you want the program to work.