FindBacktrace: Add imported library

This is to avoid (a future version of) Qt from having to wrap
FindBacktrace like [1].

[1] https://code.qt.io/cgit/qt/qtbase.git/tree/cmake/FindWrapBacktrace.cmake

4 files changed, 75 insertions, 0 deletions

diff --git a/Tests/CMakeLists.txt b/Tests/CMakeLists.txt
index 96beecc..68f1d69 100644
--- a/Tests/CMakeLists.txt
+++ b/Tests/CMakeLists.txt
@@ -1447,6 +1447,7 @@ if(BUILD_TESTING)
   _mod
   IN ITEMS
       ALSA
+      Backtrace
       BLAS
       Boost
       BZip2
diff --git a/Tests/FindBacktrace/CMakeLists.txt b/Tests/FindBacktrace/CMakeLists.txt
new file mode 100644
index 0000000..8ee2a4d
--- /dev/null
+++ b/Tests/FindBacktrace/CMakeLists.txt
@@ -0,0 +1,10 @@
+add_test(NAME FindBacktrace.Test COMMAND
+  ${CMAKE_CTEST_COMMAND} -C $<CONFIGURATION>
+  --build-and-test
+  "${CMake_SOURCE_DIR}/Tests/FindBacktrace/Test"
+  "${CMake_BINARY_DIR}/Tests/FindBacktrace/Test"
+  ${build_generator_args}
+  --build-project TestFindBacktrace
+  --build-options ${build_options}
+  --test-command ${CMAKE_CTEST_COMMAND} -V -C $<CONFIGURATION>
+  )
diff --git a/Tests/FindBacktrace/Test/CMakeLists.txt b/Tests/FindBacktrace/Test/CMakeLists.txt
new file mode 100644
index 0000000..7f5d8ec
--- /dev/null
+++ b/Tests/FindBacktrace/Test/CMakeLists.txt
@@ -0,0 +1,11 @@
+cmake_minimum_required(VERSION 3.29)
+project(TestFindBLAS C)
+include(CTest)
+
+find_package(Backtrace REQUIRED)
+
+add_executable(test_tgt backtrace.c)
+target_link_libraries(test_tgt Backtrace::Backtrace)
+target_compile_options(test_tgt PUBLIC -rdynamic -fno-omit-frame-pointer)
+target_link_options(test_tgt PUBLIC -rdynamic -fno-omit-frame-pointer)
+add_test(NAME test_tgt COMMAND test_tgt)
diff --git a/Tests/FindBacktrace/Test/backtrace.c b/Tests/FindBacktrace/Test/backtrace.c
new file mode 100644
index 0000000..1a60b14
--- /dev/null
+++ b/Tests/FindBacktrace/Test/backtrace.c
@@ -0,0 +1,53 @@
+/* This is the code from `man backtrace_symbols`, reformatted, and without
+ * requiring a command-line argument */
+
+#include <execinfo.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+
+#define BT_BUF_SIZE 100
+
+void myfunc3(void)
+{
+  int nptrs;
+  void* buffer[BT_BUF_SIZE];
+  char** strings;
+
+  nptrs = backtrace(buffer, BT_BUF_SIZE);
+  printf("backtrace() returned %d addresses\n", nptrs);
+
+  /* The call backtrace_symbols_fd(buffer, nptrs, STDOUT_FILENO)
+     would produce similar output to the following: */
+
+  strings = backtrace_symbols(buffer, nptrs);
+  if (strings == NULL) {
+    perror("backtrace_symbols");
+    exit(EXIT_FAILURE);
+  }
+
+  for (size_t j = 0; j < nptrs; j++)
+    printf("%s\n", strings[j]);
+
+  free(strings);
+}
+
+static void /* "static" means don't export the symbol... */
+myfunc2(void)
+{
+  myfunc3();
+}
+
+void myfunc(int ncalls)
+{
+  if (ncalls > 1)
+    myfunc(ncalls - 1);
+  else
+    myfunc2();
+}
+
+int main(int argc, char* argv[])
+{
+  myfunc(5);
+  exit(EXIT_SUCCESS);
+}