Documentation errata for IBM XL C for AIX, V12.1

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Abstract

This page contains corrections and additions to the product documentation shipped with IBM XL C for AIX, V12.1.

Content

Installation Guide

The following corrections and additions apply to the IBM XL C for AIX, V12.1 Installation Guide:

Chapter: Before installing XL C

Section: The installation image and filesets

Topic: Runtime debug memory routine filesets

This topic lists the runtime debug memory routine filesets V5.4.

should read:

This topic lists the runtime debug memory routine filesets V5.5.

Topic: Utilization reporting tool fileset

This topic lists the utilization reporting tool filesets V1.1.

should read:

This topic lists the utilization reporting tool filesets V1.2.

All references to the version of the utilization reporting tool (urt) in the Installation Guide should be changed to V1.2.

Section: System prerequisites

lslpp -L bos.adt.include bos.adt.lib bos.adt.libm bos.loc.* bos.rte bos.rte.libc

should read:

lslpp -L bos.adt.include bos.adt.lib bos.adt.libm bos.loc.\* bos.rte bos.rte.libc


Compiler Reference
The following corrections and additions apply to the IBM XL C for AIX, V12.1 Compiler Reference:

Chapter: Tracking and reporting compiler usage

Section: Understanding the utilization reporting tool

The tool is located in the /opt/ibmurt/1.1/bin directory.

should read:

The tool is located in the /opt/ibmurt/1.2/bin directory.

A default configuration file ibmurt.cfg is provided in the /opt/ibmurt/1.1/config directory.

should read:

A default configuration file ibmurt.cfg is provided in the /opt/ibmurt/1.2/config directory.

All references to the version of the utilization reporting tool (urt) in the Compiler Reference should be changed to V1.2.

Chapter: Compiler options reference

Section: Individual option descriptions

Topic: -qdfp
The following new information is added:

Note: To use decimal floating-point types and literals, you must also enable specific code in header files by defining the __STDC_WANT_DEC_FP__ macro at compiler time. See Examples.

Examples
To compile myprogram.c so that the compiler supports decimal floating-point types and literals, enter:
xlc myprogram.c -qarch=pwr7 -qdfp -D__STDC_WANT_DEC_FP__

Topic: -qdigraph

Purpose

Enables recognition of digraph key combinations or keywords to represent characters not found on some keyboards.

should read:

Enables recognition of digraph key combinations to represent characters that are not found on some keyboards. Digraph key combinations include <:, <%, and so on.

Topic: -qinline

Defaults

  • -qnoinline
  • At an optimization level of -O0, the default is -qinline=noauto
  • At optimization levels of -O2 and higher, the default is -qinline=auto
  • -qinline=auto:level=5 is the default suboption of -qinline

should read:
  • -qnoinline
  • At optimization levels of -O2 and higher, the default is -qinline=noauto
  • -qinline=auto:level=5 is the default suboption of -qinline

Topic: -qsuppress

Examples

If your program normally results in the following output:
“myprogram.c”, line 1.1:1506-224 (I) Incorrect #pragma ignored

you can suppress the message by compiling with:
xlc myprogram.c -qsuppress

should read:

If your program normally results in the following output:
“myprogram.c”, line 1.1:1506-224 (I) Incorrect #pragma ignored

you can suppress the message by compiling with:
xlc myprogram.c -qsuppress =1506-224

Topic: -qtune

The following rows in the Acceptable -qarch/-qtune combinations table:

-qarch option Default -qtune setting Available -qtune settings
pwr4 pwr4 auto | pwr4 | pwr5 | pwr7 | ppc970 | balanced
pwr5 pwr5 auto | pwr5 | pwr7 | balanced
pwr5x pwr5 auto | pwr5 | pwr7 | balanced

Should read:

-qarch option Default -qtune setting Available -qtune settings
pwr4 pwr4 auto | pwr4 | pwr5 | pwr6 | pwr7 | ppc970 | balanced
pwr5 pwr5 auto | pwr5 | pwr6 | pwr7 | balanced
pwr5x pwr5 auto | pwr5 | pwr6 | pwr7 | balanced


Chapter: Compiler pragmas reference

Section: Individual pragmas descriptions

Topic: #pragma reg_killed_by

fs
    Floating-point and status control register

Should read:

fsr
    Floating-point and status control register


Chapter: Compiler built-in functions

Section: GCC atomic memory access built-in functions

The data types of the parameters that are supported in these functions include Boolean type and any integral scalar type of 1, 2, 4 or 8 bytes, listed as follows.

should read:

In the prototype of each function, the parameter types T, U, and V can be of pointer or integral type. U and V can also be of real floating-point type, but only when T is of integral type. The following tables list the integral and floating-point types that are supported by these built-in functions.

Table 1. Supported data types

should read:

Table 1. Supported integral data types

The following data type should be added to Table 1. Supported integral data types.

_Bool

The following table should be added:

Table 2. Supported floating-point data types
float
double
long double


Optimization and Programming Guide
The following corrections and additions apply to the IBM XL C for AIX, V12.1 Optimization and Programming Guide:

Chapter: Handling floating-point operations

Topic: Compiling a decimal floating-point program

The following text:

If you are using decimal floating-point formats in your programs, use the -qdfp option when you compile them. For example, to compile the following Hello World program dfp_hello.c, the compiler invocation is:
xlc -qdfp dfp_hello.c

Should read:

If you are using decimal floating-point formats in your programs, use the -qdfp option and define the __STDC_WANT_DEC_FP__ macro when you compile them.

For example, to compile dfp_hello.c, use the following compiler invocation:
xlc dfp_hello.c -qdfp -qarch=pwr7 -D__STDC_WANT_DEC_FP__


Chapter: Optimizing your applications

Section: Using profile-directed feedback

The following restriction note should be added under Step 1:

Restriction: When you run an application that is compiled with -qpdf1, you must end the application using normal methods, including reaching the end of the execution for the main function and calling the exit() function in libc (stdlib.h) for C programs. System calls exit() and _Exit() are considered abnormal termination methods and are not supported. Using abnormal program termination might result in incomplete instrumentation data generated by using the PDF file or PDF data not being generated at all.

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Document information


More support for:

XL C for AIX
Documentation

Software version:

12.1

Operating system(s):

AIX

Reference #:

1584857

Modified date:

2013-11-20

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