strchr

1) Finds the first occurrence of ch (after conversion to char as if by (char)ch) in the null-terminated byte string pointed to by str (each character interpreted as unsigned char). The terminating null character is considered to be a part of the string and can be found when searching for '\0'.

2) Type-generic function equivalent to (1). Let T be an unqualified character object type.

• If str is of type const T*, the return type is const char*.
• Otherwise, if str is of type T*, the return type is char*.
• Otherwise, the behavior is undefined.

If a macro definition of each of these generic functions is suppressed to access an actual function (e.g. if (strchr) or a function pointer is used), the actual function declaration (1) becomes visible.