STRCHR(3) Linux Programmer's Manual STRCHR(3)
strchr, strrchr, strchrnul - locate character in string
char *strchr(const char *s, int c);
char *strrchr(const char *s, int c);
#define _GNU_SOURCE /* See feature_test_macros(7) */
char *strchrnul(const char *s, int c);
The strchr() function returns a pointer to the first occurrence of the character c in the string s.
The strrchr() function returns a pointer to the last occurrence of the character c in the string s.
The strchrnul() function is like strchr() except that if c is not found in s, then it returns a pointer to the null byte at the end of s,
rather than NULL.
Here "character" means "byte"; these functions do not work with wide or multibyte characters.
The strchr() and strrchr() functions return a pointer to the matched character or NULL if the character is not found. The terminating null
byte is considered part of the string, so that if c is specified as '