#include <string.h>
The <string.h> header shall define NULL and size_t as described in <stddef.h>.
The <string.h> header shall define the locale_t type as described in <locale.h>.
The following shall be declared as functions and may also be defined as macros. Function prototypes shall be provided for use with ISO C standard compilers.
void *memccpy(void *restrict, const void *restrict, int, size_t); void *memchr(const void *, int, size_t); int memcmp(const void *, const void *, size_t); void *memcpy(void *restrict, const void *restrict, size_t); void *memmove(void *, const void *, size_t); void *memset(void *, int, size_t); char *stpcpy(char *restrict, const char *restrict); char *stpncpy(char *restrict, const char *restrict, size_t); char *strcat(char *restrict, const char *restrict); char *strchr(const char *, int); int strcmp(const char *, const char *); int strcoll(const char *, const char *); int strcoll_l(const char *, const char *, locale_t); char *strcpy(char *restrict, const char *restrict); size_t strcspn(const char *, const char *); char *strdup(const char *); char *strerror(int); char *strerror_l(int, locale_t); int strerror_r(int, char *, size_t); size_t strlen(const char *); char *strncat(char *restrict, const char *restrict, size_t); int strncmp(const char *, const char *, size_t); char *strncpy(char *restrict, const char *restrict, size_t); char *strndup(const char *, size_t); size_t strnlen(const char *, size_t); char *strpbrk(const char *, const char *); char *strrchr(const char *, int); char *strsignal(int); size_t strspn(const char *, const char *); char *strstr(const char *, const char *); char *strtok(char *restrict, const char *restrict); char *strtok_r(char *restrict, const char *restrict, char **restrict); size_t strxfrm(char *restrict, const char *restrict, size_t); size_t strxfrm_l(char *restrict, const char *restrict, size_t, locale_t);
Inclusion of the <string.h> header may also make visible all symbols from <stddef.h>.
The following sections are informative.
The System Interfaces volume of POSIX.1-2017, Section 2.2, The Compilation Environment, memccpy(), memchr(), memcmp(), memcpy(), memmove(), memset(), strcat(), strchr(), strcmp(), strcoll(), strcpy(), strcspn(), strdup(), strerror(), strlen(), strncat(), strncmp(), strncpy(), strpbrk(), strrchr(), strsignal(), strspn(), strstr(), strtok(), strxfrm()
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