-qro

Purpose

Specifies the storage type for string literals.

When -qro or #pragma strings (readonly) is in effect, strings are placed in read-only memory. When -qnoro or #pragma strings (writeable) is in effect, strings are placed in read-write memory.

Syntax


Option syntax

        .-ro---.   
>>- -q--+-noro-+-----------------------------------------------><


Pragma syntax

                          .-readonly--.      
>>-#--pragma--strings--(--+-writeable-+--)---------------------><

Defaults

C only Strings are read-only for all invocation commands except cc. If the cc invocation command is used, strings are writeable.

C++ only Strings are read-only.

Parameters

readonly (pragma only): String literals are to be placed in read-only memory.
writeable (pragma only): String literals are to be placed in read-write memory.

Usage

Placing string literals in read-only memory can improve runtime performance and save storage. However, code that attempts to modify a read-only string literal may generate a memory error.

The pragmas must appear before any source statements in a file.