% limb manual
% u64_fmt(3)
% limb 0.1.0
% 2023-07-24
# NAME
u64_fmt, u64_fmtg, u64_0fmt - write an u64 as decimal value into a byte array
u64_xfmt, u64_0xfmt - write an u64 as hexadecimal value into a byte array
u64_ofmt, u64_0ofmt - write an u64 as octal value into a byte array
u64_bfmt, u64_0bfmt - write an u64 as binary value into a byte array
# SYNOPSIS
#include <limb/u64.h>
```pre hl
size_t u64_fmt(char *<em>s</em>, u64 <em>u</em>)
size_t u64_0fmt(char *<em>s</em>, u64 <em>u</em>, size_t <em>min</em>)
size_t u64_fmtg(char *<em>s</em>, u64 <em>u</em>)
size_t u64_0fmtg(char *<em>s</em>, u64 <em>u</em>, size_t <em>min</em>)
size_t u64_xfmt(char *<em>s</em>, u64 <em>u</em>)
size_t u64_0xfmt(char *<em>s</em>, u64 <em>u</em>, size_t <em>min</em>)
size_t u64_ofmt(char *<em>s</em>, u64 <em>u</em>)
size_t u64_0ofmt(char *<em>s</em>, u64 <em>u</em>, size_t <em>min</em>)
size_t u64_bfmt(char *<em>s</em>, u64 <em>u</em>)
size_t u64_0bfmt(char *<em>s</em>, u64 <em>u</em>, size_t <em>min</em>)
```
# DESCRIPTION
The `u64_fmt`() macro will write into `s` the value of `u` in decimal.
The `u64_0fmt`() macro will write into `s` the value of `u` in decimal,
prefixing it with leading zeroes if it requires less than `min` characters to do
so.
The `u64_fmtg`() and `u64_0fmtg`() macros are similar, only they will use a
coma (`,`) as thousand separator as needed.
The `u64_xfmt`() and `u64_0xfmt`() macros are similar, only putting the value
of `u` in hexadecimal.
The `u64_ofmt`() and `u64_0ofmt`() macros are similar, only putting the value
of `u` in octal.
The `u64_bfmt`() and `u64_0bfmt`() macros are similar, only putting the value
of `u` in binary.
It is possible to use `NULL` as `s` to only have length computation performed.
! INFO: Generic functions
! Note that those are macros to [u64_fmt_generic](3) and [u64_0fmt_generic](3).
## Constants
Some constants are available if needed, e.g. to allocate a buffer large enough :
: *U64_FMT*
:: Maximum number of `char` needed to hold a decimal string
: *U64_FMTG*
:: Maximum number of `char` needed to hold a thousand-separated decimal string
: *U64_XFMT*
:: Maximum number of `char` needed to hold an hexadecimal string
: *U64_OFMT*
:: Maximum number of `char` needed to hold an octal string
: *U64_BFMT*
:: Maximum number of `char` needed to hold a binary string
Note that all of those include an extra `char` for a proper NUL-terminated
string.
# RETURN VALUE
All of these return the length of the string written into `s`, or required to
do so when `s` is `NULL`