diff --git a/src/audio_file.cc b/src/audio_file.cc
index cbc7293..044c8ce 100644
--- a/src/audio_file.cc
+++ b/src/audio_file.cc
@@ -103,7 +103,7 @@ int audioFileOpen(const char* fname, int flags, ...)
         audioFile->soundDecoder = soundDecoderInit(audioFileSoundDecoderReadHandler, audioFile->fileHandle, &(audioFile->field_14), &(audioFile->field_10), &(audioFile->fileSize));
         audioFile->fileSize *= 2;
     } else {
-        audioFile->fileSize = compat_filelength(fileno(stream));
+        audioFile->fileSize = getFileSize(stream);
     }
 
     audioFile->position = 0;
diff --git a/src/dfile.cc b/src/dfile.cc
index 569ba54..39024b6 100644
--- a/src/dfile.cc
+++ b/src/dfile.cc
@@ -61,7 +61,7 @@ DBase* dbaseOpen(const char* filePath)
 
     // Get file size, and reposition stream to read footer, which contains two
     // 32-bits ints.
-    int fileSize = compat_filelength(fileno(stream));
+    int fileSize = getFileSize(stream);
     if (fseek(stream, fileSize - sizeof(int) * 2, SEEK_SET) != 0) {
         goto err;
     }
diff --git a/src/platform_compat.cc b/src/platform_compat.cc
index 5f15704..5ead0cf 100644
--- a/src/platform_compat.cc
+++ b/src/platform_compat.cc
@@ -291,3 +291,14 @@ char* compat_strdup(const char* string)
 {
     return SDL_strdup(string);
 }
+
+// It's a replacement for compat_filelength(fileno(stream)) on platforms without
+// fileno defined.
+long getFileSize(FILE* stream)
+{
+    long originalOffset = ftell(stream);
+    fseek(stream, 0, SEEK_END);
+    long filesize = ftell(stream);
+    fseek(stream, originalOffset, SEEK_SET);
+    return filesize;
+}
diff --git a/src/platform_compat.h b/src/platform_compat.h
index 5bb4f57..70807d4 100644
--- a/src/platform_compat.h
+++ b/src/platform_compat.h
@@ -40,5 +40,6 @@ int compat_remove(const char* path);
 int compat_rename(const char* oldFileName, const char* newFileName);
 void compat_windows_path_to_native(char* path);
 char* compat_strdup(const char* string);
+long getFileSize(FILE* stream);
 
 #endif /* PLATFORM_COMPAT_H */
diff --git a/src/xfile.cc b/src/xfile.cc
index 40ce71d..57cd82b 100644
--- a/src/xfile.cc
+++ b/src/xfile.cc
@@ -441,7 +441,7 @@ long xfileGetSize(XFile* stream)
         fileSize = 0;
         break;
     default:
-        fileSize = compat_filelength(fileno(stream->file));
+        fileSize = getFileSize(stream->file);
         break;
     }