http://benji3up2kxewkqfcq7buxk2xd6zwy3zggnurkrm3l4cvwy2iipvyyad.onion/mirrors/gmpdoc/Formatted-Output-Strings.html
‘ m ’ and ‘ p ’ depend on the C library. a A hex floats, C99 style c character d decimal integer e E scientific format float f fixed point float i same as d g G fixed or scientific float m strerror string, GLIBC style n store characters written so far o octal integer p pointer s string u unsigned integer x X hex integer ‘ o ’, ‘ x ’ and ‘ X ’ are unsigned for the standard C types, but for
types ‘ Z ’, ‘ Q ’ and ‘ N ’ they are signed