NAME
strstr, strcasestr - locate a substring SYNOPSIS
#include
char *strstr(const char *haystack, const char *needle); #define GNUSOURCE /* See featuretestmacros(7) */
#include
char *strcasestr(const char *haystack, const char *needle); DESCRIPTION The strstr() function finds the first occurrence of the substring nee‐ dle in the string haystack. The terminating null bytes ('\0') are not compared. The strcasestr() function is like strstr(), but ignores the case of both arguments. RETURN VALUE These functions return a pointer to the beginning of the substring, or NULL if the substring is not found. ATTRIBUTES For an explanation of the terms used in this section, see attributes(7). ┌─────────────┬───────────────┬────────────────┐ │Interface │ Attribute │ Value │ ├─────────────┼───────────────┼────────────────┤ │strstr() │ Thread safety │ MT-Safe │ ├─────────────┼───────────────┼────────────────┤
│strcasestr() │ Thread safety │ MT-Safe locale │ └─────────────┴───────────────┴────────────────┘ CONFORMING TO The strstr() function conforms to C89 and C99. The strcasestr() func‐ tion is a nonstandard extension. BUGS Early versions of Linux libc (like 4.5.26) would not allow an empty needle argument for strstr(). Later versions (like 4.6.27) work cor‐ rectly, and return haystack when needle is empty. SEE ALSO index(3), memchr(3), rindex(3), strcasecmp(3), strchr(3), string(3), strpbrk(3), strsep(3), strspn(3), strtok(3), wcsstr(3) COLOPHON
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GNU 2011-09-28 STRSTR(3)