HP aC++/HP C Programmer's Guide (B3901-90036; A.06.26; September 2011)

• RWSTD_MULTI_THREAD / _RWSTD_MULTI_THREAD

Required by Rogue Wave standard library header files and libraries.

RWSTD_MULTI_THREAD is used by libstd 1.2.1. _RWSTD_MULTI_THREAD is used

by libstd 2.2.1 when compiling with -AA.

• _POSIX_C_SOURCE=199506L

Required by pthread.

• libpthread.*

Kernel thread library used on 11.x systems

See “Using Threads” (page 202) for more information.

NOTE: Make sure that -mt is used consistently at compile and link times. When you

link with -mt, everything must be compiled with -mt, even if you do not think your file

will be used in a threaded application. When you incorrectly mix and match with -mt,

you get a runtime abort with the following message:

aCC runtime: Use of "-mt" must be consistent during both compilation and linking.

To find the library or object that is missing -mt, use /usr/ccs/bin/footprints and

look for the following:

-mt [(off) 1] -mt [on 1] (Or not present)

The number 1 above is the count of objects with that -mt setting. Not present implies

the source was not compiled with a recent compiler that contains this information.

+O[no]autopar

The +Oautopar option enables automatic parallelization of loops that are deemed safe

and profitable by the loop transformer.

Usage:

This optimization allows applications to exploit otherwise idle resources on multicore or

multiprocessor systems by automatically transforming serial loops into multithreaded

parallel code. When the +Oautopar option is used at optimization levels +O3 and

above, the compiler automatically parallelizes those loops that are deemed safe and

profitable by the loop transformer.

Automatic parallelization can be combined with manual parallelization through the use

of OpenMP directives and the +Oopenmp option. When both +Oopenmp and +Oautopar

options are specified, then any existing OpenMP directives take precedence, and the

compiler will only consider auto-parallelizing other loops that are not controlled by those

directives.

Parallel Processing Options 81