strspn - get length of a substring
size_t strspn(const char *s1, const char *s2);
[CX] The functionality described on this reference page is aligned with the ISO C standard. Any conflict between the requirements described here and the ISO C standard is unintentional. This volume of IEEE Std 1003.1-2001 defers to the ISO C standard.
The strspn() function shall compute the length (in bytes) of the maximum initial segment of the string pointed to by s1 which consists entirely of bytes from the string pointed to by s2.
The strspn() function shall return the length of s1; no return value is reserved to indicate an error.
No errors are defined.
strcspn(), the Base Definitions volume of IEEE Std 1003.1-2001, <string.h>
First released in Issue 1. Derived from Issue 1 of the SVID.
The RETURN VALUE section is updated to indicate that strspn() returns the length of s, and not s itself as was previously stated.