---
name: "fmt_ulong0"
section: "3"
platform: "linux"
package: "libowfat-dev"
version: "0.32-5"
release: "Debian 13 (Trixie)"
platforms: ["linux"]
url: "https://new.carta.tech/fmt_ulong0"
---

# fmt\_ulong0(3)

write a zero-padded ASCII representation of an unsigned long integer

## NAME

fmt\_ulong0 - write a zero-padded ASCII representation of an unsigned long integer

## SYNTAX

**#include \<libowfat/fmt.h\>**

size\_t **fmt\_ulong0**(char \**dest*, unsigned long *source*,\
                         size\_t *n*);

## DESCRIPTION

fmt\_ulong0 writes an ASCII representation ('0' to '9', base 10) of *source* to *dest* and returns the number of bytes written. The output is padded with '0'-bytes until it encompasses at least *n* bytes, but it will not be truncated if it does not fit.

fmt\_ulong0 does not append \\0.

If *dest* equals FMT\_LEN (i.e. is zero), fmt\_ulong0 returns the number of bytes it would have written.

For convenience, fmt.h defines the integer FMT\_ULONG to be big enough to contain every possible fmt\_ulong output plus \\0.

## SEE ALSO

[scan\_ulong(3)](/scan_ulong/3.md), [fmt\_ulong(3)](/fmt_ulong/3.md)