NAME

strcspn — get the length of a complementary substring

SYNOPSIS

#include <string.h>

size_t strcspn(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 strcspn() function shall compute the length (in bytes) of the maximum initial segment of the string pointed to by s1 which consists entirely of bytes not from the string pointed to by s2.

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

RETURN VALUE

The strcspn() function shall return the length of the computed segment of the string pointed to by s1; 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

strspn

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 strcspn() returns the length of s1, and not s1 itself as was previously stated.

Issue 6

The Open Group Corrigendum U030/1 is applied. The text of the RETURN VALUE section is updated to indicate that the computed segment length is returned, not the s1 length.

Issue 8

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