HP aC++/HP C A.06.20 Programmer's Guide

The following example directs the compiler to search in the directory include for
#include files.
aCC -I include file.C
-I-
[-Idirs] -I- [-Idirs]
[-Idirs] indicates an optional list of -Idirectory specifications in which a directory
name cannot begin with a hyphen (-) character.
The -I- option allows you to override the default -Idirectory search-path. This
feature is called view-pathing. Specifying -I- serves two purposes:
1. It changes the compiler’s search-path for quote enclosed (" ") file names in a
#include directive to the following order:
a. The directory named in the -Ioption.
b. The standard include directories /opt/aCC/include* and /usr/include.
The preprocessor does not search the directory of the including file.
2. It separates the search-path list for quoted and angle-bracketed include files.
Angle-bracket enclosed file names in a #include directive are searched for only
in the -Idirectories specified after -I- on the command-line. Quoted include files
are searched for in the directories that both precede and follow the -I- option.
The standard aCC include directories (/usr/include and /opt/aCC/include*)
are always searched last for both types of include files.
Usage:
View-pathing can be particularly valuable for medium to large sized projects. For
example, imagine that a project comprises two sets of directories. One set contains
development versions of some of the headers that the programmer currently modifies.
A mirror set contains the official sources.
Without view-pathing, there is no way to completely replace the default -Idirectory
search-path with one customized specifically for project development.
With view-pathing, you can designate and separate official directories from development
directories and enforce an unconventional search-path order. For quote enclosed
headers, the preprocessor can include any header files located in development directories
and, in the absence of these, include headers located in the official directories.
If -I- is not specified, view-pathing is turned off. This is the default.
Examples:
With view-pathing off, the following example obtains all the quoted include files from
dir1 only if they are not found in the directory of a.C and from dir2 only if they are
not found in dir1. Finally, if necessary, the standard include directories are searched.
56 Command-Line Options