master: make cppad_static_lib = true the default on windows .

Author: bradbell

CMakeLists.txt

@@ -217,15 +217,25 @@ command_line_arg(cppad_tape_addr_type "unsigned int" STRING
 "type used to identify variables on one tape, size must be <= sizeof(size_t)"
 )
 #
-# cppad_static_lib
-command_line_arg(cppad_static_lib FALSE BOOL
-   "If true (false) the cppad library will be static (shared)"
-)
-#
 # cppad_debug_and_release
 command_line_arg(cppad_debug_and_release TRUE BOOL
    "If true the cppad library and tests will be able to mix debug and release"
 )
+#
+# cppad_static_lib
+STRING( REGEX MATCH "^MSYS"    is_msys     "${CMAKE_SYSTEM_NAME}" )
+STRING( REGEX MATCH "^CYGWIN"  is_cygwin   "${CMAKE_SYSTEM_NAME}" )
+STRING( REGEX MATCH "^Windows" is_windows  "${CMAKE_SYSTEM_NAME}" )
+IF( is_msys OR is_cygwin OR is_windows )
+   SET(default_cppad_static_lib TRUE)
+ELSE( )
+   SET(default_cppad_static_lib FALSE)
+ENDIF( )
+#
+# cppad_static_lib
+command_line_arg(cppad_static_lib ${default_cppad_static_lib} BOOL
+   "If true (false) the cppad library will be static (shared)"
+)
 # ----------------------------------------------------------------------------
 #
 # Ensure c++11 support

appendix/whats_new/2025.xrst

@@ -8,6 +8,7 @@
    dll
    jit
    rpath
+   msys
 }
 
 Release Notes for 2025
@@ -18,12 +19,14 @@ mm-dd
 
 02-09
 =====
-Systems that use windows dll files would always build a static
+Systems that use windows dll files,
+(msys, cygwin, and windows) would always build a static
 version of the cppad library; i.e., the
 `cmake@cppad_static_lib` flag was ignored in this case.
 This has been changed so that the cppad_static_lib flag is always respected.
-If you have trouble linking on a windows system, perhaps setting
-this flag to true will help.
+The default value for *cppad_static_lib* on msys, cygwin, and windows is true
+and on other systems it is false; i.e., if you do not specify cppad_static_lib
+you will get the same result as before this change.
 
 
 02-02

xrst/install/cmake.xrst

@@ -410,8 +410,8 @@ will build the  corresponding documentation in the
 
 cppad_static_lib
 ****************
-The default value for this option is false.
-If it is true (false)
+The default value for this option is true on
+``msys``, ``cygwin`` and ``Windows`` and false otherwise.
 the cppad library will be a static (shared) library.
 If the target system uses windows dlls, this setting should be true and
 if it is false, a warning will be issued and it will be ignored.