--- src/core/Platform.h	2019-03-28 13:12:57.000000000 +0800
+++ src/core/Platform.h	2023-08-04 22:13:55.000000000 +0800
@@ -122,7 +122,12 @@
 
 // TODO: Add proper endian detection using architecture / compiler mojo
 //       In the meantime, hardcode to x86
-#define OCIO_LITTLE_ENDIAN 1  // This is correct on x86
+#if defined(__BYTE_ORDER__) && defined(__ORDER_BIG_ENDIAN__) && \
+    __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
+    #define OCIO_BIG_ENDIAN
+#else
+    #define OCIO_LITTLE_ENDIAN // This is correct on x86
+#endif
 
     /*
      * Mutex classes


--- src/core/FileFormatIridasLook.cpp	2019-03-28 13:12:57.000000000 +0800
+++ src/core/FileFormatIridasLook.cpp	2023-08-04 22:15:26.000000000 +0800
@@ -132,20 +132,22 @@
             
             unsigned char * fvalbytes = reinterpret_cast<unsigned char *>(&fval);
             
-#if OCIO_LITTLE_ENDIAN
+#if defined(OCIO_LITTLE_ENDIAN)
             // Since incoming values are little endian, and we're on little endian
             // preserve the byte order
             fvalbytes[0] = (unsigned char) (asciinums[1] | (asciinums[0] << 4));
             fvalbytes[1] = (unsigned char) (asciinums[3] | (asciinums[2] << 4));
             fvalbytes[2] = (unsigned char) (asciinums[5] | (asciinums[4] << 4));
             fvalbytes[3] = (unsigned char) (asciinums[7] | (asciinums[6] << 4));
-#else
+#elif defined(OCIO_BIG_ENDIAN)
             // Since incoming values are little endian, and we're on big endian
             // flip the byte order
             fvalbytes[3] = (unsigned char) (asciinums[1] | (asciinums[0] << 4));
             fvalbytes[2] = (unsigned char) (asciinums[3] | (asciinums[2] << 4));
             fvalbytes[1] = (unsigned char) (asciinums[5] | (asciinums[4] << 4));
             fvalbytes[0] = (unsigned char) (asciinums[7] | (asciinums[6] << 4));
+#else
+    #error "Endianness is unknown."
 #endif
             return true;
         }