NAME

strspn — get length of a substring

SYNOPSIS

#include <string.h>

size_t strspn(const char *s1, const char *s2);


DESCRIPTION

^[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 POSIX.1-2024 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.

^[CX] The strspn() function shall not change the setting of errno on valid input.

RETURN VALUE

The strspn() function shall return the computed length; no return value is reserved to indicate an error.

ERRORS

No errors are defined.

EXAMPLES

None.

APPLICATION USAGE

None.

RATIONALE

None.

FUTURE DIRECTIONS

None.

SEE ALSO

strcspn

XBD <string.h>

CHANGE HISTORY

First released in Issue 1. Derived from Issue 1 of the SVID.

Issue 5

The RETURN VALUE section is updated to indicate that strspn() returns the length of s, and not s itself as was previously stated.

Issue 7

SD5-XSH-ERN-182 is applied.

Issue 8

Austin Group Defect 448 is applied, adding a requirement that strspn() does not change the setting of errno on valid input.