feat: add native SWMR support for concurrent read/write

.gitignore

@@ -0,0 +1,3 @@
+build/
+.envrc
+*.h5

API.md

@@ -322,6 +322,32 @@ class(*), intent(out) :: attrval(:)  !< character, real, integer
 call h%delete_attr(dname, attr)
 ```
 
+## Iterate over all datasets in a group
+
+```fortran
+call h%iterate(group, callback)
+
+character(*), intent(in) :: group
+subroutine callback(group_name, object_name, object_type)
+  character(len=*), intent(in) :: group_name
+  character(len=*), intent(in) :: object_name
+  character(len=*), intent(in) :: object_type
+end subroutine
+```
+
+## Visit recursively all datasets starting from a group
+
+```fortran
+call h%visit(group, callback)
+
+character(*), intent(in) :: group
+subroutine callback(group_name, object_name, object_type)
+  character(len=*), intent(in) :: group_name
+  character(len=*), intent(in) :: object_name
+  character(len=*), intent(in) :: object_type
+end subroutine
+```
+
 ## high level operations
 
 These are single-call operations that are slower than the object-oriented methods above.

CMakeLists.txt

@@ -51,6 +51,7 @@ endif()
 # --- h5fortran library
 
 add_library(h5fortran)
+
 target_include_directories(h5fortran PUBLIC
 $<BUILD_INTERFACE:${CMAKE_Fortran_MODULE_DIRECTORY}>
 $<INSTALL_INTERFACE:${CMAKE_INSTALL_INCLUDEDIR}>

flake.nix

@@ -0,0 +1,243 @@
+{
+  description = "h5fortran development shells";
+
+  inputs = {
+    nixpkgs.url = "github:NixOS/nixpkgs/nixos-24.11";
+    flake-utils.url = "github:numtide/flake-utils";
+  };
+
+  outputs =
+    {
+      self,
+      nixpkgs,
+      flake-utils,
+    }:
+    flake-utils.lib.eachDefaultSystem (
+      system:
+      let
+        pkgs = import nixpkgs {
+          inherit system;
+          config = {
+            allowUnfree = true;
+          };
+        };
+
+        common-build-tools = with pkgs; [
+          cmake
+          ninja
+          pkg-config
+          git
+        ];
+
+        mkGccShell =
+          {
+            name,
+            gcc-pkg,
+            gfortran-pkg,
+            packages ? [ ],
+            shellHookExtra ? "",
+          }:
+          pkgs.mkShell {
+            inherit name;
+            packages =
+              common-build-tools
+              ++ [
+                gcc-pkg
+                gfortran-pkg
+                pkgs.hdf5
+                pkgs.zlib
+                pkgs.python3
+              ]
+              ++ packages;
+
+            shellHook = ''
+              export CC=${gcc-pkg}/bin/gcc
+              export FC=${gfortran-pkg}/bin/gfortran
+              export CXX=${gcc-pkg}/bin/g++
+              echo "h5fortran: ${name}"
+              echo "CC: $CC  FC: $FC  CXX: $CXX"
+              echo "HDF5: ${pkgs.hdf5.dev}"
+              ${shellHookExtra}
+            '';
+
+            HDF5_DIR = "${pkgs.hdf5.dev}";
+          };
+      in
+      {
+        devShells.default = mkGccShell {
+          name = "h5fortran-gcc-default";
+          gcc-pkg = pkgs.gcc14;
+          gfortran-pkg = pkgs.gfortran14;
+          shellHookExtra = ''echo "Build: cmake -Bbuild -G Ninja --workflow --preset default"'';
+        };
+
+        devShells.gcc-old = mkGccShell {
+          name = "h5fortran-gcc-11";
+          gcc-pkg = pkgs.gcc11;
+          gfortran-pkg = pkgs.gfortran11;
+          shellHookExtra = ''echo "Build: cmake -Bbuild -G Ninja --workflow --preset default"'';
+        };
+
+        devShells.gcc-new = mkGccShell {
+          name = "h5fortran-gcc-14";
+          gcc-pkg = pkgs.gcc14;
+          gfortran-pkg = pkgs.gfortran14;
+          shellHookExtra = ''echo "Build: cmake -Bbuild -G Ninja --workflow --preset default"'';
+        };
+
+        devShells.flang = pkgs.mkShell {
+          name = "h5fortran-flang";
+          packages =
+            common-build-tools
+            ++ [
+              pkgs.llvmPackages.clang
+              pkgs.llvmPackages.flang
+              pkgs.llvmPackages.llvm
+              pkgs.llvmPackages.libomp
+              pkgs.hdf5
+              pkgs.zlib
+            ];
+
+          shellHook = ''
+            export CC=${pkgs.llvmPackages.clang}/bin/clang
+            export CXX=${pkgs.llvmPackages.clang}/bin/clang++
+            export FC=${pkgs.llvmPackages.flang}/bin/flang-new
+            echo "h5fortran: LLVM/Flang + HDF5 + CMake + Ninja"
+            echo "HDF5: ${pkgs.hdf5.dev}"
+          '';
+
+          HDF5_DIR = "${pkgs.hdf5.dev}";
+        };
+
+        devShells.fpm = pkgs.mkShell {
+          name = "h5fortran-fpm";
+          packages =
+            common-build-tools
+            ++ [
+              pkgs.gcc14
+              pkgs.gfortran14
+              pkgs.hdf5
+              pkgs.zlib
+              pkgs.fpm
+              pkgs.python3
+            ];
+
+          shellHook = ''
+            export CC=${pkgs.gcc14}/bin/gcc
+            export FC=${pkgs.gfortran14}/bin/gfortran
+            export CXX=${pkgs.gcc14}/bin/g++
+            export FPM_FFLAGS="-I${pkgs.hdf5.dev}/include"
+            export FPM_LDFLAGS="-L${pkgs.hdf5.lib}/lib"
+            echo "h5fortran: fpm + GCC + HDF5"
+            echo "Build: fpm build"
+          '';
+        };
+
+        devShells.testing = mkGccShell {
+          name = "h5fortran-testing";
+          gcc-pkg = pkgs.gcc14;
+          gfortran-pkg = pkgs.gfortran14;
+          packages = with pkgs; [
+            valgrind
+            gcovr
+          ];
+          shellHookExtra = ''
+            echo "Tools: valgrind, gcovr, python (h5py/numpy)"
+            echo "Build: cmake -Bbuild -G Ninja --workflow --preset default"
+          '';
+        };
+
+        devShells.cmake-old = pkgs.mkShell {
+          name = "h5fortran-cmake-old";
+          packages = with pkgs; [
+            cmake_3_24
+            ninja
+            pkg-config
+            gcc14
+            gfortran14
+            hdf5
+            zlib
+            git
+          ];
+
+          shellHook = ''
+            export CC=${pkgs.gcc14}/bin/gcc
+            export FC=${pkgs.gfortran14}/bin/gfortran
+            export CXX=${pkgs.gcc14}/bin/g++
+            echo "h5fortran: CMake 3.24 (old) + GCC 14 + HDF5 + Ninja"
+            echo "HDF5: ${pkgs.hdf5.dev}"
+          '';
+
+          HDF5_DIR = "${pkgs.hdf5.dev}";
+        };
+
+        devShells.oneapi = pkgs.mkShell {
+          name = "h5fortran-oneapi";
+          packages = with pkgs;
+            common-build-tools
+            ++ [
+              pkgs.intel-oneapi.hpc
+              pkgs.hdf5-fortran
+              pkgs.zlib
+              pkgs.python3
+              pkgs.stdenv.cc
+            ];
+
+          shellHook = ''
+            # Source Intel oneAPI environment
+            if [ -d /opt/intel/oneapi ]; then
+              source /opt/intel/oneapi/setvars.sh >/dev/null 2>&1
+            fi
+
+            # Create icx wrapper with proper linker paths
+            _NIX_GLIBC_LIB=$(dirname $(gcc -print-file-name=Scrt1.o))
+            _NIX_GCC_CRT=$(dirname $(gcc -print-file-name=crtbeginS.o))
+            _NIX_GCC_SLIB=$(dirname $(gcc -print-file-name=libgcc_s.so))
+            _ICX_WRAPPER=$(mktemp /tmp/icx-wrapper-XXXXXX)
+            cat > "$_ICX_WRAPPER" << EOF
+#!/usr/bin/env bash
+exec ${pkgs.intel-oneapi.hpc}/bin/icx -L$_NIX_GLIBC_LIB -L$_NIX_GCC_CRT -L$_NIX_GCC_SLIB -B$_NIX_GLIBC_LIB -B$_NIX_GCC_CRT "\$@"
+EOF
+            chmod +x "$_ICX_WRAPPER"
+
+            export CC="$_ICX_WRAPPER"
+            export CXX=${pkgs.intel-oneapi.hpc}/bin/icpx
+            export FC=${pkgs.intel-oneapi.hpc}/bin/ifx
+            export PATH=${pkgs.intel-oneapi.hpc}/bin:$PATH
+            export LD_LIBRARY_PATH=${pkgs.intel-oneapi.hpc}/lib:$_NIX_GLIBC_LIB:$_NIX_GCC_CRT:$_NIX_GCC_SLIB:$LD_LIBRARY_PATH
+
+            echo "h5fortran: Intel oneAPI (ifx/icx) + HDF5 + CMake + Ninja"
+            echo "CC: $CC  FC: $FC"
+            echo "HDF5: ${pkgs.hdf5-fortran.dev}"
+          '';
+
+          HDF5_DIR = "${pkgs.hdf5-fortran.dev}";
+        };
+
+        devShells.coverage = mkGccShell {
+          name = "h5fortran-coverage";
+          gcc-pkg = pkgs.gcc14;
+          gfortran-pkg = pkgs.gfortran14;
+          packages = with pkgs; [
+            gcovr
+            lcov
+          ];
+          shellHookExtra = ''
+            echo "Tools: gcovr, lcov"
+            echo "Build: cmake -Bbuild -G Ninja --preset coverage"
+          '';
+        };
+
+        devShells.shared = mkGccShell {
+          name = "h5fortran-shared";
+          gcc-pkg = pkgs.gcc14;
+          gfortran-pkg = pkgs.gfortran14;
+          shellHookExtra = ''
+            echo "Build: cmake -Bbuild -G Ninja --workflow --preset shared"
+          '';
+        };
+
+        packages = { };
+      }
+    );
+}

fpm.toml

@@ -74,6 +74,18 @@ main = "test_shape.f90"
 name = "string"
 main = "test_string.f90"
 
+[[test]]
+name = "visit"
+main = "test_visit.f90"
+
+[[test]]
+name = "iterate"
+main = "test_iterate.f90"
+
 [[test]]
 name = "version"
 main = "test_version.f90"
+
+[[test]]
+name = "swmr"
+main = "test_swmr.f90"