Option to use compiled fmt library

src/cmake/Config.cmake.in

@@ -12,7 +12,7 @@ if (NOT @OPENIMAGEIO_CONFIG_DO_NOT_FIND_IMATH@ AND NOT OPENIMAGEIO_CONFIG_DO_NOT
                     HINTS @Imath_DIR@)
 endif ()
 
-if (NOT @fmt_LOCAL_BUILD@ AND NOT @OIIO_INTERNALIZE_FMT@)
+if (NOT @fmt_LOCAL_BUILD@ AND (NOT @OIIO_INTERNALIZE_FMT@ OR @OIIO_USE_COMPILED_FMT@))
     find_dependency(fmt)
 endif ()
 

src/cmake/externalpackages.cmake

@@ -243,11 +243,21 @@ checked_find_package (Robinmap REQUIRED
 
 # fmtlib
 set_option (OIIO_INTERNALIZE_FMT "Copy fmt headers into <install>/include/OpenImageIO/detail/fmt" ON)
+set_option (OIIO_USE_COMPILED_FMT "Link against compiled fmt::fmt instead of header-only fmt" OFF)
+if (OIIO_USE_COMPILED_FMT)
+    set (OIIO_USE_COMPILED_FMT_VALUE 1)
+else ()
+    set (OIIO_USE_COMPILED_FMT_VALUE 0)
+endif ()
 checked_find_package (fmt REQUIRED
                       VERSION_MIN 9.0
                       BUILD_LOCAL missing
                      )
-get_target_property(FMT_INCLUDE_DIR fmt::fmt-header-only INTERFACE_INCLUDE_DIRECTORIES)
+if (OIIO_USE_COMPILED_FMT)
+    get_target_property(FMT_INCLUDE_DIR fmt::fmt INTERFACE_INCLUDE_DIRECTORIES)
+else ()
+    get_target_property(FMT_INCLUDE_DIR fmt::fmt-header-only INTERFACE_INCLUDE_DIRECTORIES)
+endif ()
 
 
 ###########################################################################

src/include/OpenImageIO/detail/fmt.h

@@ -9,9 +9,15 @@
 #include <OpenImageIO/platform.h>
 #include <OpenImageIO/type_traits.h>
 
-// We want the header-only implementation of fmt
-#ifndef FMT_HEADER_ONLY
-#    define FMT_HEADER_ONLY
+// By default OIIO uses the header-only implementation of fmt. Builds that opt
+// into compiled external fmt must use the same mode in OIIO and consumers.
+#ifndef OIIO_USE_COMPILED_FMT
+#    define OIIO_USE_COMPILED_FMT 0
+#endif
+#if !OIIO_USE_COMPILED_FMT
+#    ifndef FMT_HEADER_ONLY
+#        define FMT_HEADER_ONLY
+#    endif
 #endif
 
 #if OIIO_VERSION_LESS(3, 1, 2)

src/include/OpenImageIO/oiioversion.h.in

@@ -47,6 +47,7 @@
 #define OIIO_VERSION_PATCH @PROJECT_VERSION_PATCH@
 #define OIIO_VERSION_TWEAK @PROJECT_VERSION_TWEAK@
 #define OIIO_VERSION_RELEASE_TYPE @PROJECT_VERSION_RELEASE_TYPE@
+#define OIIO_USE_COMPILED_FMT @OIIO_USE_COMPILED_FMT_VALUE@
 
 // Preprocessor utility: stringize
 #define OIIO_STRINGIZE_HELPER(a) #a

src/libutil/CMakeLists.txt

@@ -83,7 +83,11 @@ function (setup_oiio_util_library targetname)
 
     if (OIIO_INTERNALIZE_FMT OR fmt_LOCAL_BUILD)
         add_dependencies(${targetname} fmt_internal_target)
-    else ()
+    endif ()
+    if (OIIO_USE_COMPILED_FMT)
+        target_link_libraries (${targetname}
+                               PUBLIC fmt::fmt)
+    elseif (NOT OIIO_INTERNALIZE_FMT AND NOT fmt_LOCAL_BUILD)
         target_link_libraries (${targetname}
                                PUBLIC fmt::fmt-header-only)
     endif ()

src/libutil/ustring.cpp

@@ -595,7 +595,7 @@ ustring::make_unique(string_view strref)
             std::string s = Strutil::escape_chars(strref);
             print(stderr, "IDEMPOTENT RE-HASH! |{}|\n", s);
             for (auto c : s)
-                print(stderr, c > 0 ? "{:c}" : "\\{:03o}",
+                print(stderr, fmt::runtime(c > 0 ? "{:c}" : "\\{:03o}"),
                       static_cast<unsigned char>(c));
             print(stderr, "\n");
 #    endif