Build options specification files

A build options specification (BOS) file is a text file containing macro definitions and/or HCL VersionVault special targets.

You can place temporary macros (such as CFLAGS=-g and others not to be included in a makefile permanently) in a BOS file, rather than specifying them on the clearmake command line.

By default, clearmake reads BOS files in this order:

The default BOS files:
1. The file .clearmake.options in your home directory (as indicated in the password database), which is the place for macros to be used every time you execute clearmake.
2. One or more local BOS files, each of which corresponds to one of the makefiles specified with a -f option or read by clearmake. Each BOS file has a name in the form makefile-name.options. For example:
```
makefile.options
```
```
Makefile.options
```
```
project.mk.options
```
BOS files specified in the CCASE_OPTS_SPECS environment variable.
BOS files specified on the command line with -A.

If you specify -N, clearmake does not read default BOS files.

clearmake displays the names of the BOS files it reads if you specify the -v or -d option, or if %CCASE_VERBOSITY >= 1.

For information about the contents of BOS files, see Setting up the client host.

When clearmake shops for a derived object to wink in to a build, it might find a DO from a view that is unavailable (because the view server host is down, the albd_server is not running on the server host, and so on). Attempting to fetch the configuration record of a DO from an unavailable view causes a long time-out, and the build might reference multiple DOs from the same view.

clearmake and other cleartool commands that access configuration records and DOs (lsdo, describe, catcr, diffcr) maintain a cache of tags for inaccessible views. For each view tag, the command records the time of the first unsuccessful contact. Before trying to access a view, the command checks the cache. If the tag of a view is not listed in the cache, the command tries to contact the view. If the tag of a view is listed in the cache, the command compares the time elapsed since the last attempt with the time-out period specified by the CCASE_DNVW_RETRY environment variable. If the elapsed time is greater than the time-out period, the command removes the view tag from the cache and tries to contact the view again.

Note: The cache is not persistent across clearmake sessions. Each recursive or individual invocation of clearmake attempts to contact a view whose tag might have been cached in a previous invocation.

The default time-out period is 60 minutes. To specify a different time-out period, set CCASE_DNVW_RETRY to another integer value (representing minutes). To disable the cache, set CCASE_DNVW_RETRY to 0.