Jean Hoderd wrote: > Normally I know the size of the blob I just linked in. > But suppose I didn't. Is there a way I can determine > it from within the C program? I know that by running > "objdump -x blob.o" I can see the symbol table on the > obj file, and that the symbols _binary_blob_png_end and > _binary_blob_png_size are also defined: > > SYMBOL TABLE: > 0000000000000000 l d .data 0000000000000000 .data > 0000000000000400 g .data 0000000000000000 _binary_blob_png_end > 0000000000000000 g .data 0000000000000000 _binary_blob_png_start > 0000000000000400 g *ABS* 0000000000000000 _binary_blob_png_size > > I assumed that _binary_blob_png_end was a pointer to the > end of the blob, but it doesn't seem so. Also, I always > get a segfault if I assume that _binary_blob_png_size is > an integer value. _binary_blob_png_end is a pointer to the byte just past the blob; subtracting _start from _end gets you the size. _binary_blob_png_size is a weird symbol; symbols can only be addresses, not data, so you can't reference the _size symbol directly. You must take its address, then cast from a pointer to a size_t. However, I would recommend using the _end - _start method instead, because the _size symbol will get modified if it is located in a shared library and will become useless. -- Kevin P. Fleming Director of Software Technologies Digium, Inc. - "The Genuine Asterisk Experience" (TM)
