.\" Copyright (c) 2020-2022 by Alejandro Colomar .\" and Copyright (c) 2020 by Michael Kerrisk .\" .\" SPDX-License-Identifier: Linux-man-pages-copyleft .\" .\" .TH ptrdiff_t 3type 2023-10-31 "Linux man-pages 6.7" .SH NAME ptrdiff_t \- count of elements or array index .SH LIBRARY Standard C library .RI ( libc ) .SH SYNOPSIS .nf .B #include .P .BR typedef " /* ... */ " ptrdiff_t; .fi .SH DESCRIPTION Used for a count of elements, or an array index. It is the result of subtracting two pointers. It is a signed integer type capable of storing values in the range .RB [ PTRDIFF_MIN , .BR PTRDIFF_MAX ]. .P The length modifier for .I ptrdiff_t for the .BR printf (3) and the .BR scanf (3) families of functions is .BR t , resulting commonly in .B %td or .B %ti for printing .I ptrdiff_t values. .SH STANDARDS C11, POSIX.1-2008. .SH HISTORY C89, POSIX.1-2001. .SH SEE ALSO .BR size_t (3type)