21 Strings library [strings]

21.5 Null-terminated sequence utilities [c.strings]

21.5.3 Header <cstring> synopsis [cstring.syn]

namespace std { using size_t = see [support.types.layout]; void* memcpy(void* s1, const void* s2, size_t n); void* memmove(void* s1, const void* s2, size_t n); char* strcpy(char* s1, const char* s2); char* strncpy(char* s1, const char* s2, size_t n); char* strcat(char* s1, const char* s2); char* strncat(char* s1, const char* s2, size_t n); int memcmp(const void* s1, const void* s2, size_t n); int strcmp(const char* s1, const char* s2); int strcoll(const char* s1, const char* s2); int strncmp(const char* s1, const char* s2, size_t n); size_t strxfrm(char* s1, const char* s2, size_t n); const void* memchr(const void* s, int c, size_t n); // see [library.c] void* memchr(void* s, int c, size_t n); // see [library.c] const char* strchr(const char* s, int c); // see [library.c] char* strchr(char* s, int c); // see [library.c] size_t strcspn(const char* s1, const char* s2); const char* strpbrk(const char* s1, const char* s2); // see [library.c] char* strpbrk(char* s1, const char* s2); // see [library.c] const char* strrchr(const char* s, int c); // see [library.c] char* strrchr(char* s, int c); // see [library.c] size_t strspn(const char* s1, const char* s2); const char* strstr(const char* s1, const char* s2); // see [library.c] char* strstr(char* s1, const char* s2); // see [library.c] char* strtok(char* s1, const char* s2); void* memset(void* s, int c, size_t n); char* strerror(int errnum); size_t strlen(const char* s); } #define NULL see [support.types.nullptr]
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The contents and meaning of the header <cstring> are the same as the C standard library header <string.h>.
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The functions strerror and strtok are not required to avoid data races.
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The functions memcpy and memmove are signal-safe.
Both functions implicitly create objects ([intro.object]) in the destination region of storage immediately prior to copying the sequence of characters to the destination.
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[Note 1:
The functions strchr, strpbrk, strrchr, strstr, and memchr, have different signatures in this document, but they have the same behavior as in the C standard library.
— end note]
See also: ISO C 7.24