strspn(3)

strspn3

Span a string

Usage

#include <string.h>

size_t

strspn(const char *s, const char *charset);

size_t

strcspn(const char *s, const char *charset);

Library

Standard C Library (libc, -lc)

Overview

The strspn() function spans the initial part of the null-terminated string s as long as the characters from s occur in the null-terminated string charset. In other words, it computes the string array index of the first character of s which is not in charset, else the index of the first null character.

The strcspn() function spans the initial part of the null-terminated string s as long as the characters from s do not occur in the null-terminated string charset (it spans the complement of charset). In other words, it computes the string array index of the first character of s which is also in charset, else the index of the first null character.

Return values

The strspn() and strcspn() functions return the number of characters spanned.

Releases

87 releases since FreeBSD 2.0.5-RELEASE; the text changed 42 times.

  1. 2.0.5
  2. 2.1.5–3.4
  3. 3.5–3.5.1
  4. 4.0
  5. 4.1–4.2
  6. 4.3–4.4
  7. 4.5–4.11
  8. 5.0–5.4
  9. 5.5
  10. 6.0–6.3
  11. 6.4
  12. 7.0
  13. 7.1
  14. 7.2
  15. 7.3
  16. 7.4
  17. 8.0
  18. 8.1
  19. 8.2
  20. 8.3
  21. 8.4
  22. 9.0
  23. 9.1
  24. 9.2
  25. 9.3
  26. 10.0
  27. 10.1
  28. 10.2
  29. 10.3
  30. 10.4
  31. 11.0
  32. 11.1
  33. 11.2
  34. 11.3
  35. 11.4
  36. 12.0
  37. 12.1
  38. 12.2
  39. 12.3
  40. 12.4
  41. 13.0–13.2
  42. 13.3–14.5
  43. 15.0–16.0

Standards

The strspn() and strcspn() functions conform to ISO/IEC 9899:1990 (“ISO C90”).

From base 16.0-CURRENT-20261027-61c70dc16a79 in FreeBSD 16.0-CURRENT (2026-10-27). Parsed by carta from the page's mdoc source.