diff --git a/src/libsysprof-capture/sysprof-capture-writer-cat.c b/src/libsysprof-capture/sysprof-capture-writer-cat.c
index 3fbd5858..cec252a6 100644
--- a/src/libsysprof-capture/sysprof-capture-writer-cat.c
+++ b/src/libsysprof-capture/sysprof-capture-writer-cat.c
@@ -366,7 +366,7 @@ sysprof_capture_writer_cat (SysprofCaptureWriter  *self,
                                                  frame->frame.pid,
                                                  frame->id,
                                                  frame->metadata,
-                                                 frame->frame.len - G_STRUCT_OFFSET (SysprofCaptureMetadata, metadata));
+                                                 frame->frame.len - offsetof (SysprofCaptureMetadata, metadata));
             break;
           }
 
diff --git a/src/libsysprof-capture/sysprof-capture-writer.c b/src/libsysprof-capture/sysprof-capture-writer.c
index 1e27729f..953328e8 100644
--- a/src/libsysprof-capture/sysprof-capture-writer.c
+++ b/src/libsysprof-capture/sysprof-capture-writer.c
@@ -904,7 +904,7 @@ again:
   ret = _sysprof_pwrite (self->fd,
                          &end_time,
                          sizeof (end_time),
-                         G_STRUCT_OFFSET (SysprofCaptureFileHeader, end_time));
+                         offsetof (SysprofCaptureFileHeader, end_time));
 
   if (ret < 0 && errno == EAGAIN)
     goto again;
@@ -1341,7 +1341,7 @@ do_start:
   ret = _sysprof_pwrite (self->fd,
                          &start_time,
                          sizeof (start_time),
-                         G_STRUCT_OFFSET (SysprofCaptureFileHeader, time));
+                         offsetof (SysprofCaptureFileHeader, time));
 
   if (ret < 0 && errno == EAGAIN)
     goto do_start;
@@ -1350,7 +1350,7 @@ do_end:
   ret = _sysprof_pwrite (self->fd,
                          &end_time,
                          sizeof (end_time),
-                         G_STRUCT_OFFSET (SysprofCaptureFileHeader, end_time));
+                         offsetof (SysprofCaptureFileHeader, end_time));
 
   if (ret < 0 && errno == EAGAIN)
     goto do_end;