Note: The distinctive features of clearmake, such as build auditing, derived object sharing, and build avoidance, are supported in dynamic views only. In addition, while parallel building is supported in ClearCase snapshot views, it is not supported in ClearCase LT.
The clearmake program has been designed for compatibility with existing make programs, minimizing the work necessary to switch to clearmake. There are many independently evolving variants of make, which provide different sets of extended features. clearmake does not support all features of all variants, and absolute compatibility is not guaranteed. If your makefiles use only the common extensions, they will probably work with clearmake.
Note: When building with configuration records, clearmake handles double-colon rules differently than other make programs. For details, see Building Software.
The following features are enabled when you specify –C sun:
- All extended macro-expansion operators:
- Pattern-replacement macro expansions:
- Shell-execution macro expansions:
(target-dependent) macro definitions:
You can use target-dependent macro definitions in the makefile and in the BOS file.
HOST_ARCH TARGET_ARCH HOST_MACH TARGET_MACH
- Target-dependent macros
./make.rules or /usr/share/lib/make/make.rules(SunOS 5.x)
- Sun pattern-matching rules:
- The –q command-line option (see the clearmake reference page)
- Delayed macro evaluation
- MFLAGS environment variable
VPATH: Searches for Both Targets and Dependencies
clearmake –C sun uses the VPATH search list (if there is one) to look in the current view for the target if both these conditions are true:
- The target's name is not an absolute pathname.
- There is no existing file corresponding to the target's name.
For each directory in the value of VPATH, the directory path is concatenated with the target's name; if there is an existing file at the resulting path, that file is evaluated.
This feature works whether or not clearmake uses configuration lookup (that is, either with or without the –T or –F option). If it does use configuration lookup, clearmake prefers to use a DO in the current view:
- As always, clearmake tries to reuse the candidate DO (if any) in the current view, built at the target's name.
- If such a candidate does not exist or does not qualify for reuse, clearmake searches for a candidate in the current view that was built in directories on the VPATH.
- If candidate with an appropriate name exists in a VPATH directory but is rejected by the configuration lookup algorithm, clearmake looks in the VOB database for other candidates that were built in that same VPATH directory.
- If no VPATH directory has any candidate with an appropriate name, clearmake proceeds to search the VOB database for other candidates in the directory corresponding to the target's name.
Note: In all these cases, all the DOs on which clearmake performs configuration lookup were built in a single directory.
clearmake traverses multiple VPATH directories only in deciding where to begin performing configuration lookup.
VPATH Substitutions in Build Scripts
The names of targets and dependencies in build scripts are replaced by their VPATH-elaborated counterparts. If a file is found using the VPATH, all white-space-delimited occurrences of the file's name in a build script are replaced with the pathname at which the file was found. For example:
If bar.c is found in directory depdir, and bar.o is found in directory tgtdir, and the target must be rebuilt, then this build script is executed:
Using –C sun on a non-SunOS system may cause errors because different systems have different names for their built-in makefiles. You can disable use of built-in rules with clearmake –r.
clearmake–C sun uses the SunOS arch(1) and mach(1) commands to set the values of special macros (for example, HOST_ARCH and HOST_MACH). This generates error messages on systems that do not support these commands. You can safely ignore such messages if your build scripts do not use the special macros. Some alternatives: