diff options
Diffstat (limited to 'src/engine/SCons/Action.xml')
| -rw-r--r-- | src/engine/SCons/Action.xml | 102 |
1 files changed, 60 insertions, 42 deletions
diff --git a/src/engine/SCons/Action.xml b/src/engine/SCons/Action.xml index 350082d..b519cdc 100644 --- a/src/engine/SCons/Action.xml +++ b/src/engine/SCons/Action.xml @@ -35,70 +35,88 @@ executed to build targets. By default, SCons will add to each target an implicit dependency on the command -represented by the first argument on any -command line it executes. +represented by the first argument of any +command line it executes (which is typically +the command itself). By setting such +a dependency, &SCons; can determine that +a target should be rebuilt if the command changes, +such as when a compiler is upgraded to a new version. The specific file for the dependency is found by searching the <varname>PATH</varname> variable in the -<varname>ENV</varname> -environment used to execute the command. +<varname>ENV</varname> dictionary +in the &consenv; used to execute the command. +The default is the same as +setting the &consvar; +&cv-IMPLICIT_COMMAND_DEPENDENCIES; +to a True-like value (<quote>true</quote>, +<quote>yes</quote>, +or <quote>1</quote> - but not a number +greater than one, as that has a different meaning). </para> <para> -If the construction variable -&cv-IMPLICIT_COMMAND_DEPENDENCIES; -is set to a false value -(<literal>None</literal>, -<literal>False</literal>, -<literal>0</literal>, +Action strings can be segmented by the +use of an AND operator, <literal>&&</literal>. +In a segemented string, each segment is a separate +<quote>command line</quote>, these are run +sequentially until one fails or the entire +sequence has been executed. If an +action string is segmented, then the selected +behavior of &cv-IMPLICIT_COMMAND_DEPENDENCIES; +is applied to each segment. +</para> + +<para> +If &cv-IMPLICIT_COMMAND_DEPENDENCIES; +is set to a False-like value +(<quote>none</quote>, +<quote>false</quote>, +<quote>no</quote>, +<quote>0</quote>, etc.), then the implicit dependency will not be added to the targets -built with that construction environment. +built with that &consenv;. </para> <para> -If the construction variable -&cv-IMPLICIT_COMMAND_DEPENDENCIES; -is set to <literal>2</literal> or higher, -then that number of entries in the command -string will be scanned for relative or absolute -paths. The count will reset after any -<literal>&&</literal> entries are found. -The first command in the action string and -the first after any <literal>&&</literal> -entries will be found by searching the -<varname>PATH</varname> variable in the -<varname>ENV</varname> environment used to -execute the command. All other commands will -only be found if they are absolute paths or -valid paths relative to the working directory. +If &cv-IMPLICIT_COMMAND_DEPENDENCIES; +is set to <quote>2</quote> or higher, +then that number of arguments in the command line +will be scanned for relative or absolute paths. +If any are present, they will be added as +implicit dependencies to the targets built +with that &consenv;. +The first argument in the command line will be +searched for using the <varname>PATH</varname> +variable in the <varname>ENV</varname> dictionary +in the &consenv; used to execute the command. +The other arguments will only be found if they +are absolute paths or valid paths relative +to the working directory. </para> <para> -If the construction variable -&cv-IMPLICIT_COMMAND_DEPENDENCIES; -is set to <literal>all</literal>, then -all entries in all command strings will be -scanned for relative or absolute paths. If -any are present, they will be added as +If &cv-IMPLICIT_COMMAND_DEPENDENCIES; +is set to <quote>all</quote>, +then all arguments in the command line will be +scanned for relative or absolute paths. +If any are present, they will be added as implicit dependencies to the targets built -with that construction environment. -not be added to the targets built with that -construction environment. The first command -in the action string and the first after any -<literal>&&</literal> entries will be found -by searching the <varname>PATH</varname> -variable in the <varname>ENV</varname> -environment used to execute the command. -All other commands will only be found if they +with that &consenv;. +The first argument in the command line will be +searched for using the <varname>PATH</varname> +variable in the <varname>ENV</varname> dictionary +in the &consenv; used to execute the command. +The other arguments will only be found if they are absolute paths or valid paths relative to the working directory. </para> <example_commands> -env = Environment(IMPLICIT_COMMAND_DEPENDENCIES = 0) +env = Environment(IMPLICIT_COMMAND_DEPENDENCIES=False) </example_commands> </summary> </cvar> |