<html> <head> <meta http-equiv="content-type" content="text/html; charset=UTF-8"> </head> <body> I have some trouble interpreting the float-to-word/word-to-float conversion issue in the particular case of array initialisation. This is performed by 'ML_init_array(MR_ArrayPtr array, MR_Integer size, MR_Word item)' (DEV branch, array.m:1007), using an MR_Word initialiser 'item' in a simple loop: for (i = 0; i < size; i++) { array->elements[i] = item; } Now, the manual says that some implementations have sizeof(MR_Float) > sizeof(MR_Word), which is why lists of floats should be converted using 'MR_word_to_float', as explained in the (snapshot) manual (p. 109): "The following fragment of C code illustrates the correct way to extract the head of a Mercury list of floats. MR_Float f; f = MR_word_to_float(MR_list_head(list)); Omitting the call to MR_word_to_float in the above example would yield incorrect results for implementations where ‘sizeof(MR_Float)’ is greater than ‘sizeof(MR_Word)’." A cursory look at runtime/mercury_float.h points to it being necessary when MR_BOXED_FLOAT is defined. So one would expect that the initialiser 'item', if of float type (i.e. in an 'array(float)'), would be checked as not exceeding the upper bound to MR_Word, when entered in init_2/3 (array.m:1494), at least if MR_BOXED_FLOAT is defined elsewhere. If this is the case, my guess is that the float initialiser item will not be passed unharmed to the above loop (behaviour may possibly be undefined). The code in array.m has been too stable and polished for over 20 years now for it to be a real bug, so it must be that I did not catch something. Thanks for giving me a hint. F. N. </body> </html>