Build infrastructure update

3 files changed, 54 insertions, 3 deletions

diff --git a/format/buildfile b/format/buildfile
index 4edb840..5e86503 100644
--- a/format/buildfile
+++ b/format/buildfile
@@ -1,8 +1,21 @@
-lib{format}: {hxx cxx}{format}
+lib{format}: {hxx cxx}{format} hxx{export}
+
+# For pre-releases use the complete version to make sure they cannot be used
+# in place of another pre-release or the final version.
+#
+if $abi_prerelease
+  lib{format}: bin.lib.version = @-$version
+else
+  lib{format}: bin.lib.version = @-$abi_major.$abi_minor
 
 cxx.poptions += -I$src_root
+obja{*}: cxx.poptions += -DLIBFORMAT_STATIC_BUILD
+objs{*}: cxx.poptions += -DLIBFORMAT_SHARED_BUILD
+
 lib{format}: cxx.export.poptions = -I$src_root
+liba{format}: cxx.export.poptions += -DLIBFORMAT_STATIC
+libs{format}: cxx.export.poptions += -DLIBFORMAT_SHARED
 
 # Install into the format/ subdirectory of, say, /usr/include/.
 #
-install.include = $install.include/format
+install.include = $install.include/format/
diff --git a/format/export b/format/export
new file mode 100644
index 0000000..39a37da
--- /dev/null
+++ b/format/export
@@ -0,0 +1,36 @@
+// file: format/export -*- C++ -*-
+
+#pragma once
+
+// Normally we don't export class templates (but do complete specializations),
+// inline functions, and classes with only inline member functions. Exporting
+// classes that inherit from non-exported/imported bases (e.g., std::string)
+// will end up badly. The only known workarounds are to not inherit or to not
+// export. Also, MinGW GCC doesn't like seeing non-exported function being
+// used before their inline definition. The workaround is to reorder code. In
+// the end it's all trial and error.
+
+#if defined(LIBFORMAT_STATIC)         // Using static.
+#  define LIBFORMAT_EXPORT
+#elif defined(LIBFORMAT_STATIC_BUILD) // Building static.
+#  define LIBFORMAT_EXPORT
+#elif defined(LIBFORMAT_SHARED)       // Using shared.
+#  ifdef _WIN32
+#    define LIBFORMAT_EXPORT __declspec(dllimport)
+#  else
+#    define LIBFORMAT_EXPORT
+#  endif
+#elif defined(LIBFORMAT_SHARED_BUILD) // Building shared.
+#  ifdef _WIN32
+#    define LIBFORMAT_EXPORT __declspec(dllexport)
+#  else
+#    define LIBFORMAT_EXPORT
+#  endif
+#else
+// If none of the above macros are defined, then we assume we are being used
+// by some third-party build system that cannot/doesn't signal the library
+// type. Note that this fallback works for both static and shared but in case
+// of shared will be sub-optimal compared to having dllimport.
+//
+#  define LIBFORMAT_EXPORT            // Using static or shared.
+#endif
diff --git a/format/format b/format/format
index 6c4d5f8..69350b0 100644
--- a/format/format
+++ b/format/format
@@ -4,5 +4,7 @@
 
 #include <string>
 
-std::string
+#include <format/export>
+
+LIBFORMAT_EXPORT std::string
 format (const std::string& greeting, const std::string& name);