index, rindex − locate character in string #include<strings.h> , int char *index(const char *s , int char *rindex(const char *s The function returns a pointer to the first occurrence of the character c in the string s. The function returns a pointer to the last occurrence of the character c in the string s. The terminating null byte ('\0') is considered to be a part of the strings. The and functions return a pointer to the matched character or NULL if the character is not found. For an explanation of the terms used in this section, see ┌──────────┬───────────────┬─────────┐ │Interface │ Attribute │ Value │ ├──────────┼───────────────┼─────────┤ │ │ Thread safety │ MT‐Safe │ └──────────┴───────────────┴─────────┘ 4.3BSD; marked as LEGACY in POSIX.1‐2001. POSIX.1‐2008 removes the specifications of and recommending and instead. This page is part of release 5.07 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/.