+file contains options for setting the active platform and restricting the build. \r
+The restictions are used to limit the build output by specifying build target(s), \r
+tagname(s) and architecture(s) to less than the full set of possible options. \r
+\r
+The ACTIVE_PLATFORM MUST BE SET. All other options need not be set, however by \r
+unsetting these options (by removing the line from the file, or leaving the Value \r
+empty) will result in all available build possibilites when typing build. By\r
+default EDK II can build a matrix of binaries, using different target types, tool\r
+chain tags and architectures. Options to target.txt file are as follows:\r
+\r
+ACTIVE_PLATFORM = Value REQUIRED\r
+ Where Value is the WORKSPACE relative path and filename of a Framework Platform \r
+ Definition (FPD) File. Example:\r
+\r
+ACTIVE_PLATFORM = MdePkg/MdePkg.fpd\r
+\r
+TARGET = Value OPTIONAL\r
+ Where Value is a list of one or more of the following: DEBUG, RELEASE or a User\r
+ Defined Target type, such as PERF. Example: \r
+\r
+TARGET = DEBUG RELEASE\r
+\r
+TARGET_ARCH = Value OPTIONAL\r
+ Where Value is a list of one or more supported Architectures: IA32, X64, IPF or\r
+ EBC. Example: \r
+\r
+TARGET_ARCH = IA32 X64 EBC\r
+\r
+TOOL_CHAIN_CONF = Value OPTIONAL\r
+ Where Value is the Filename of an alternate tools_def.txt file created by the\r
+ user. The alternate tools_def.txt files must be in the Tools/Conf directory.\r
+ These tool definitions are scoped to the WORKSPACE (location of the EDK \r
+ installation) and cannot be shared between WORKSPACES. (You can copy the files\r
+ from one workspace to another.) Example: \r
+\r
+TOOL_CHAIN_CONF = alfred.txt\r
+\r
+TOOL_CHAIN_TAG = Value OPTIONAL\r
+ Where Value is a list of TagName entries as defined in the tools_def.txt file.\r
+ The TagName can be used to specify different versions of a compiler, i.e., \r
+ gcc 4.0 and gcc 4.1 which will allow you to build binaries with both tool chains \r
+ during the same build - useful during testing of a new compiler tool chain, or \r
+ for changing compiler flags to check out performance with a different set of \r
+ flags than flags used for production. Example:\r
+\r
+TOOL_CHAIN_TAG = GCC40 GCC41\r
+\r
+To clear a restriction, just remove any data after the equal sign. To clear\r
+the TARGET_ARCH limitation that was set above, enter: \r
+\r
+TARGET_ARCH =\r
+\r
+-----------\r
+Copy the tools_def.template file in Tools/Conf to tools_def.txt in the same\r
+directory.\r