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strspn(3) — Linux manual page

NAME | LIBRARY | SYNOPSIS | DESCRIPTION | RETURN VALUE | ATTRIBUTES | STANDARDS | HISTORY | SEE ALSO | COLOPHON 

strspn(3)                Library Functions Manual               strspn(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

       strspn()
              The strspn() function calculates the length (in bytes) of
              the initial segment of s which consists entirely of bytes
              in accept.

       strcspn()
              The strcspn() function calculates the length of the initial
              segment of s which consists entirely of bytes not in
              reject.

              It is equivalent to

                  (strpbrk(s, reject) ?: strnul(s)) - s

RETURN VALUE         top

       The strspn() function returns the number of bytes in the initial
       segment of s which consist only of bytes from accept.

       The strcspn() function returns the number of bytes in the initial
       segment of s which are not in the string reject.

ATTRIBUTES         top

       For an explanation of the terms used in this section, see
       attributes(7).
       โ”Œโ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”ฌโ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”ฌโ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”
       โ”‚ Interface                            โ”‚ Attribute     โ”‚ Value   โ”‚
       โ”œโ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”ผโ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”ผโ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”ค
       โ”‚ strspn(), strcspn()                  โ”‚ Thread safety โ”‚ MT-Safe โ”‚
       โ””โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”ดโ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”ดโ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”˜

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

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Linux man-pages 6.18            2026-02-25                      strspn(3)

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

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