不在。string.h中只有一些宏定义,如下:
/* string.h
Definitions for memory and string functions.
Copyright (c) Borland International 1987,1988
All Rights Reserved.
*/
#if __STDC__
#define _Cdecl
#else
#define _Cdecl cdecl
#endif
#ifndef _SIZE_T
#define _SIZE_T
typedef unsigned size_t;
#endif
void *_Cdecl memccpy (void *dest, const void *src, int c, size_t n);
void *_Cdecl memchr (const void *s, int c, size_t n);
int _Cdecl memcmp (const void *s1, const void *s2, size_t n);
void *_Cdecl memcpy (void *dest, const void *src, size_t n);
int _Cdecl memicmp (const void *s1, const void *s2, size_t n);
void *_Cdecl memmove (void *dest, const void *src, size_t n);
void *_Cdecl memset (void *s, int c, size_t n);
void _Cdecl movedata(unsigned srcseg, unsigned srcoff, unsigned dstseg,
unsigned dstoff, size_t n);
char *_Cdecl stpcpy (char *dest, const char *src);
char *_Cdecl strcat (char *dest, const char *src);
char *_Cdecl strchr (const char *s, int c);
int _Cdecl strcmp (const char *s1, const char *s2);
char *_Cdecl strcpy (char *dest, const char *src);
size_t _Cdecl strcspn (const char *s1, const char *s2);
char *_Cdecl strdup (const char *s);
char *_Cdecl strerror(int errnum);
int _Cdecl stricmp (const char *s1, const char *s2);
size_t _Cdecl strlen (const char *s);
char *_Cdecl strlwr (char *s);
char *_Cdecl strncat (char *dest, const char *src, size_t maxlen);
int _Cdecl strncmp (const char *s1, const char *s2, size_t maxlen);
char *_Cdecl strncpy (char *dest, const char *src, size_t maxlen);
int _Cdecl strnicmp(const char *s1, const char *s2, size_t maxlen);
char *_Cdecl strnset (char *s, int ch, size_t n);
char *_Cdecl strpbrk (const char *s1, const char *s2);
char *_Cdecl strrchr (const char *s, int c);
char *_Cdecl strrev (char *s);
char *_Cdecl strset (char *s, int ch);
size_t _Cdecl strspn (const char *s1, const char *s2);
char *_Cdecl strstr (const char *s1, const char *s2);
char *_Cdecl strtok (char *s1, const char *s2);
char *_Cdecl strupr (char *s);
/* compatibility with other compilers */
#define strcmpi(s1,s2) stricmp(s1,s2)
#define strncmpi(s1,s2,n) strnicmp(s1,s2,n)
#if !__STDC__
char *_Cdecl _strerror (const char *s);
#endif