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strspn(3) — Linux manual page

strspn(3)                Library Functions Manualstrspn(3)

NAME        top

       strspn, strcspn - get length of a prefix substring

LIBRARY        top

       Standard C library (libc,-lc)

SYNOPSIS        top

#include <string.h>size_t strspn(const char *s, const char *accept);size_t strcspn(const char *s, const char *reject);

DESCRIPTION        top

       Thestrspn() function calculates the length (in bytes) of the       initial segment ofs which consists entirely of bytes inaccept.       Thestrcspn() function calculates the length of the initial       segment ofs which consists entirely of bytes not inreject.

RETURN VALUE        top

       Thestrspn() function returns the number of bytes in the initial       segment ofs which consist only of bytes fromaccept.       Thestrcspn() function returns the number of bytes in the initial       segment ofs which are not in the stringreject.

ATTRIBUTES        top

       For an explanation of the terms used in this section, seeattributes(7).       ┌──────────────────────────────────────┬───────────────┬─────────┐       │Interface│Attribute│Value│       ├──────────────────────────────────────┼───────────────┼─────────┤       │strspn(),strcspn()                  │ Thread safety │ MT-Safe │       └──────────────────────────────────────┴───────────────┴─────────┘

STANDARDS        top

       C11, POSIX.1-2008.

HISTORY        top

       POSIX.1-2001, C89, SVr4, 4.3BSD.

SEE ALSO        top

memchr(3),strchr(3),string(3),strpbrk(3),strsep(3),strstr(3),strtok(3),wcscspn(3),wcsspn(3)

COLOPHON        top

       This page is part of theman-pages (Linux kernel and C library       user-space interface documentation) project.  Information about       the project can be found at        ⟨https://www.kernel.org/doc/man-pages/⟩.  If you have a bug report       for this manual page, see       ⟨https://git.kernel.org/pub/scm/docs/man-pages/man-pages.git/tree/CONTRIBUTING⟩.       This page was obtained from the tarball man-pages-6.15.tar.gz       fetched from       ⟨https://mirrors.edge.kernel.org/pub/linux/docs/man-pages/⟩ on       2025-08-11.  If you discover any rendering problems in this HTML       version of the page, or you believe there is a better or more up-       to-date source for the page, or you have corrections or       improvements to the information in this COLOPHON (which isnot       part of the original manual page), send a mail to       man-pages@man7.orgLinux man-pages 6.15            2025-05-17strspn(3)

Pages that refer to this page:memchr(3), strchr(3), string(3), strpbrk(3), strsep(3), strstr(3), strtok(3), wcscspn(3), wcsspn(3), signal-safety(7)

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