Modernize FindZeroMQ.cmake and fix some ZeroMQ related compile bugs

cmake/DetectOptions.cmake

@@ -339,9 +339,15 @@ endif()
 
 # ZeroMQ
 if(ADIOS2_USE_ZeroMQ STREQUAL AUTO)
-    find_package(ZeroMQ 4.1)
+  find_package(ZeroMQ 4.1 CONFIG)
+  if(NOT ZeroMQ_FOUND)
+    find_package(ZeroMQ 4.1 MODULE)
+  endif()
 elseif(ADIOS2_USE_ZeroMQ)
-    find_package(ZeroMQ 4.1 REQUIRED)
+  find_package(ZeroMQ 4.1 CONFIG)
+  if(NOT ZeroMQ_FOUND)
+    find_package(ZeroMQ 4.1 MODULE REQUIRED)
+  endif()
 endif()
 if(ZeroMQ_FOUND)
     set(ADIOS2_HAVE_ZeroMQ TRUE)

cmake/FindZeroMQ.cmake

@@ -2,49 +2,28 @@
 #
 # SPDX-License-Identifier: Apache-2.0
 
+if(ZeroMQ_FOUND)
+  return()
+endif()
 
-if(NOT ZeroMQ_FOUND)
-  if((NOT ZeroMQ_ROOT) AND (NOT (ENV{ZeroMQ_ROOT} STREQUAL "")))
-    set(ZeroMQ_ROOT "$ENV{ZeroMQ_ROOT}")
-  endif()
-  if(ZeroMQ_ROOT)
-    set(ZeroMQ_INCLUDE_OPTS HINTS ${ZeroMQ_ROOT}/include NO_DEFAULT_PATHS)
-    set(ZeroMQ_LIBRARY_OPTS
-      HINTS ${ZeroMQ_ROOT}/lib ${ZeroMQ_ROOT}/lib64
-      NO_DEFAULT_PATHS
-    )
-  endif()
+# Use find_package instead of find_dependency because we do NOT want PkgConfig to be REQUIRED.
+# If PkgConfig is missing, we simply stop without producing a fatal error.
+find_package(PkgConfig QUIET)
+if(NOT PkgConfig_FOUND)
+    return()
+endif()
 
-  find_path(ZeroMQ_INCLUDE_DIR zmq.h ${ZeroMQ_INCLUDE_OPTS})
-  find_library(ZeroMQ_LIBRARY zmq ${ZeroMQ_LIBRARY_OPTS})
-  if(ZeroMQ_INCLUDE_DIR)
-    file(STRINGS ${ZeroMQ_INCLUDE_DIR}/zmq.h _ver_strings
-      REGEX "ZMQ_VERSION_[^ ]* [0-9]+"
-    )
-    foreach(v IN LISTS _ver_strings)
-      string(REGEX MATCH "ZMQ_VERSION_([^ ]+) ([0-9]+)" v "${v}")
-      set(ZeroMQ_VERSION_${CMAKE_MATCH_1} ${CMAKE_MATCH_2})
-    endforeach()
-    set(ZeroMQ_VERSION
-      ${ZeroMQ_VERSION_MAJOR}.${ZeroMQ_VERSION_MINOR}.${ZeroMQ_VERSION_PATCH}
-    )
-  endif()
+pkg_check_modules(libzmq IMPORTED_TARGET libzmq)
 
-  include(FindPackageHandleStandardArgs)
-  find_package_handle_standard_args(ZeroMQ
-    FOUND_VAR ZeroMQ_FOUND
-    VERSION_VAR ZeroMQ_VERSION
-    REQUIRED_VARS ZeroMQ_LIBRARY ZeroMQ_INCLUDE_DIR
-  )
-  if(ZeroMQ_FOUND)
-    set(ZeroMQ_INCLUDE_DIRS ${ZeroMQ_INCLUDE_DIR})
-    set(ZeroMQ_LIBRARIES ${ZeroMQ_LIBRARY})
-    if(ZeroMQ_FOUND AND NOT TARGET ZeroMQ::ZMQ)
-      add_library(ZeroMQ::ZMQ UNKNOWN IMPORTED)
-      set_target_properties(ZeroMQ::ZMQ PROPERTIES
-        IMPORTED_LOCATION             "${ZeroMQ_LIBRARY}"
-        INTERFACE_INCLUDE_DIRECTORIES "${ZeroMQ_INCLUDE_DIR}"
-      )
-    endif()
-  endif()
+include(FindPackageHandleStandardArgs)
+find_package_handle_standard_args(
+  ZeroMQ
+  REQUIRED_VARS libzmq_FOUND
+  VERSION_VAR libzmq_VERSION
+)
+# Create alias target to match imported target name of the native package
+# Only create the alias if ZeroMQ was successfully found.
+# This prevents creating an alias when version checks failed or the module is incomplete.
+if(ZeroMQ_FOUND AND TARGET PkgConfig::libzmq)
+  add_library(libzmq ALIAS PkgConfig::libzmq)
 endif()

examples/hello/datamanKokkos/CMakeLists.txt

@@ -24,8 +24,6 @@ if(NOT TARGET adios2_core)
     list(APPEND _components MPI)
   endif()
 
-  find_package(ZeroMQ 4.1 QUIET)
-
   find_package(Kokkos 3.7 QUIET)
   if(Kokkos_FOUND AND DEFINED Kokkos_CXX_COMPILER)
     set(CMAKE_CXX_COMPILER "${Kokkos_CXX_COMPILER}")

examples/hello/datamanReader/CMakeLists.txt

@@ -24,8 +24,6 @@ if(NOT TARGET adios2_core)
     list(APPEND _components MPI)
   endif()
 
-  find_package(ZeroMQ 4.1 QUIET)
-
   find_package(ADIOS2 REQUIRED COMPONENTS ${_components})
 endif()
 

examples/hello/datamanWriter/CMakeLists.txt

@@ -24,8 +24,6 @@ if(NOT TARGET adios2_core)
     list(APPEND _components MPI)
   endif()
 
-  find_package(ZeroMQ 4.1 QUIET)
-
   find_package(ADIOS2 REQUIRED COMPONENTS ${_components})
 endif()
 

source/adios2/CMakeLists.txt

@@ -360,7 +360,7 @@ if(ADIOS2_HAVE_ZeroMQ)
     toolkit/zmq/zmqreqrep/ZmqReqRep.cpp
     toolkit/zmq/zmqpubsub/ZmqPubSub.cpp
   )
-  target_link_libraries(adios2_core PRIVATE ZeroMQ::ZMQ)
+  target_link_libraries(adios2_core PRIVATE libzmq)
 endif()
 
 if(ADIOS2_HAVE_DataMan)

source/adios2/toolkit/zmq/zmqpubsub/ZmqPubSub.cpp

@@ -35,14 +35,14 @@ ZmqPubSub::~ZmqPubSub()
 void ZmqPubSub::OpenPublisher(const std::string &address)
 {
     m_ZmqContext = zmq_ctx_new();
-    if (not m_ZmqContext)
+    if (!m_ZmqContext)
     {
         helper::Throw<std::runtime_error>("Toolkit", "ZmqPubSub", "OpenPublisher",
                                           "creating zmq context failed");
     }
 
     m_ZmqSocket = zmq_socket(m_ZmqContext, ZMQ_PUB);
-    if (not m_ZmqSocket)
+    if (!m_ZmqSocket)
     {
         helper::Throw<std::runtime_error>("Toolkit", "ZmqPubSub", "OpenPublisher",
                                           "creating zmq socket failed");
@@ -59,14 +59,14 @@ void ZmqPubSub::OpenPublisher(const std::string &address)
 void ZmqPubSub::OpenSubscriber(const std::string &address, const size_t bufferSize)
 {
     m_ZmqContext = zmq_ctx_new();
-    if (not m_ZmqContext)
+    if (!m_ZmqContext)
     {
         helper::Throw<std::runtime_error>("Toolkit", "ZmqPubSub", "OpenSubscriber",
                                           "creating zmq context failed");
     }
 
     m_ZmqSocket = zmq_socket(m_ZmqContext, ZMQ_SUB);
-    if (not m_ZmqSocket)
+    if (!m_ZmqSocket)
     {
         helper::Throw<std::runtime_error>("Toolkit", "ZmqPubSub", "OpenSubscriber",
                                           "creating zmq socket failed");
@@ -86,7 +86,7 @@ void ZmqPubSub::OpenSubscriber(const std::string &address, const size_t bufferSi
 
 void ZmqPubSub::Send(std::shared_ptr<std::vector<char>> buffer)
 {
-    if (buffer != nullptr and buffer->size() > 0)
+    if (buffer != nullptr && buffer->size() > 0)
     {
         zmq_send(m_ZmqSocket, buffer->data(), buffer->size(), ZMQ_DONTWAIT);
     }

source/adios2/toolkit/zmq/zmqreqrep/ZmqReqRep.cpp

@@ -18,7 +18,7 @@ namespace zmq
 ZmqReqRep::ZmqReqRep()
 {
     m_Context = zmq_ctx_new();
-    if (not m_Context)
+    if (!m_Context)
     {
         helper::Throw<std::runtime_error>("Toolkit", "ZmqReqRep", "ZmqReqRep",
                                           "creating zmq context failed");
@@ -77,7 +77,7 @@ void ZmqReqRep::OpenReplier(const std::string &address, const int timeout,
     m_ReceiverBuffer.reserve(receiverBufferSize);
 
     m_Socket = zmq_socket(m_Context, ZMQ_REP);
-    if (not m_Socket)
+    if (!m_Socket)
     {
         helper::Throw<std::runtime_error>("Toolkit", "ZmqReqRep", "OpenReplier",
                                           "creating zmq socket failed");