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Top Forums Programming Fastest way to find the length of string in c Post 302656685 by hergp on Friday 15th of June 2012 08:17:26 AM
Old 06-15-2012
I don't think, your approach will gain any speed. Most implementation of strlen use assembler code to maximize speed. Some CPU architectures can do strlen in a single assembler instruction. You can't top that with whatever C code you might come up with.

For reference: in x86 assembler, the relevant instruction is repne scasb

BTW: strlen and other simple string functions are ofter compiled as inline without calling a library function.
 

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STRLEN(3)						     Linux Programmer's Manual							 STRLEN(3)

NAME
strlen - calculate the length of a string SYNOPSIS
#include <string.h> size_t strlen(const char *s); DESCRIPTION
The strlen() function calculates the length of the string pointed to by s, excluding the terminating null byte (''). RETURN VALUE
The strlen() function returns the number of characters in the string pointed to by s. ATTRIBUTES
For an explanation of the terms used in this section, see attributes(7). +----------+---------------+---------+ |Interface | Attribute | Value | +----------+---------------+---------+ |strlen() | Thread safety | MT-Safe | +----------+---------------+---------+ CONFORMING TO
POSIX.1-2001, POSIX.1-2008, C89, C99, C11, SVr4, 4.3BSD. SEE ALSO
string(3), strnlen(3), wcslen(3), wcsnlen(3) COLOPHON
This page is part of release 4.15 of the Linux man-pages project. A description of the project, information about reporting bugs, and the latest version of this page, can be found at https://www.kernel.org/doc/man-pages/. GNU
2016-03-15 STRLEN(3)
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