Test static linking with LINK_SEARCH_START_STATIC

Add "LinkStatic" test that links a static executable against "libm.a".
Pass both "/usr/lib/libm.a" and "-lm" to target_link_libraries to
trigger the link type logic for both cases.  If CMake incorrectly
switches the link type to shared for "-lm" then the link will fail.

2 files changed, 32 insertions, 0 deletions

diff --git a/Tests/LinkStatic/CMakeLists.txt b/Tests/LinkStatic/CMakeLists.txt
new file mode 100644
index 0000000..2062c43
--- /dev/null
+++ b/Tests/LinkStatic/CMakeLists.txt
@@ -0,0 +1,27 @@
+cmake_minimum_required(VERSION 2.8.4.20110303 FATAL_ERROR)
+project(LinkStatic C)
+
+if(NOT "${CMAKE_C_COMPILER_ID}" MATCHES "^(GNU)$")
+  message(FATAL_ERROR "This test works only with the GNU compiler!")
+endif()
+
+find_library(MATH_LIBRARY NAMES libm.a)
+if(MATH_LIBRARY)
+  get_filename_component(MATH_LIB_DIR ${MATH_LIBRARY} PATH)
+  link_directories(${MATH_LIB_DIR})
+  # Name the library both with a full path and as "-lm" to
+  # activate the link type switching code for both cases.
+  # If the second one links shared then the link will fail.
+  set(MATH_LIBRARIES ${MATH_LIBRARY} -lm)
+else()
+  message(FATAL_ERROR "Cannot find libm.a needed for this test")
+endif()
+
+add_executable(LinkStatic LinkStatic.c)
+target_link_libraries(LinkStatic ${MATH_LIBRARIES})
+
+# Enable static linking.
+set(LinkStatic_FLAG "-static" CACHE STRING "Flag to link statically")
+set_property(TARGET LinkStatic PROPERTY LINK_FLAGS "${LinkStatic_FLAG}")
+set_property(TARGET LinkStatic PROPERTY LINK_SEARCH_START_STATIC 1)
+#set_property(TARGET LinkStatic PROPERTY LINK_SEARCH_END_STATIC 1) # insufficient
diff --git a/Tests/LinkStatic/LinkStatic.c b/Tests/LinkStatic/LinkStatic.c
new file mode 100644
index 0000000..3600977
--- /dev/null
+++ b/Tests/LinkStatic/LinkStatic.c
@@ -0,0 +1,5 @@
+#include <math.h>
+int main(void)
+{
+  return (int)sin(0);
+}