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C string.h library functions:
All C inbuilt functions which are declared in string.h header file are given below. The source code for string.h header file is also given below for your reference.
List of inbuilt C functions in string.h file:
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String functions
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Description
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| strcat ( ) | Concatenates str2 at the end of str1 |
| strncat ( ) | Appends a portion of string to another |
| strcpy ( ) | Copies str2 into str1 |
| strncpy ( ) | Copies given number of characters of one string to another |
| strlen ( ) | Gives the length of str1 |
| strcmp ( ) | Returns 0 if str1 is same as str2. Returns <0 if strl < str2. Returns >0 if str1 > str2 |
| strcmpi ( ) | Same as strcmp() function. But, this function negotiates case. “A” and “a” are treated as same. |
| strchr ( ) | Returns pointer to first occurrence of char in str1 |
| strrchr ( ) | last occurrence of given character in a string is found |
| strstr ( ) | Returns pointer to first occurrence of str2 in str1 |
| strrstr ( ) | Returns pointer to last occurrence of str2 in str1 |
| strdup ( ) | Duplicates the string |
| strlwr ( ) | Converts string to lowercase |
| strupr ( ) | Converts string to uppercase |
| strrev ( ) | Reverses the given string |
| strset ( ) | Sets all character in a string to given character |
| strnset ( ) | It sets the portion of characters in a string to given character |
| strtok ( ) | Tokenizing given string using delimiter |
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string functions
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Description
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| memset() | It is used to initialize a specified number of bytes to null or any other value in the buffer |
| memcpy() | It is used to copy a specified number of bytes from one memory to another |
| memmove() | It is used to copy a specified number of bytes from one memory to another or to overlap on same memory. |
| memcmp() | It is used to compare specified number of characters from two buffers |
| memicmp() | It is used to compare specified number of characters from two buffers regardless of the case of the characters |
| memchr() | It is used to locate the first occurrence of the character in the specified string |
Source code for string.h header file:
Please find the source code for string.h header file below. This code is taken from DevC++ compiler files for your reference.
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/* * string.h * This file has no copyright assigned and is placed in the Public Domain. * This file is a part of the mingw-runtime package. * No warranty is given; refer to the file DISCLAIMER within the package. * * Definitions for memory and string functions. * */ #ifndef _STRING_H_ #define _STRING_H_ /* All the headers include this file. */ #include <_mingw.h> /* * Define size_t, wchar_t and NULL */ #define __need_size_t #define __need_wchar_t #define __need_NULL #ifndef RC_INVOKED #include <stddef.h> #endif /* Not RC_INVOKED */ #ifndef RC_INVOKED #ifdef __cplusplus extern "C" { #endif /* * Prototypes of the ANSI Standard C library string functions. */ _CRTIMP void* __cdecl memchr (const void*, int, size_t) __MINGW_ATTRIB_PURE; _CRTIMP int __cdecl memcmp (const void*, const void*, size_t) __MINGW_ATTRIB_PURE; _CRTIMP void* __cdecl memcpy (void*, const void*, size_t); _CRTIMP void* __cdecl memmove (void*, const void*, size_t); _CRTIMP void* __cdecl memset (void*, int, size_t); _CRTIMP char* __cdecl strcat (char*, const char*); _CRTIMP char* __cdecl strchr (const char*, int) __MINGW_ATTRIB_PURE; _CRTIMP int __cdecl strcmp (const char*, const char*) __MINGW_ATTRIB_PURE; _CRTIMP int __cdecl strcoll (const char*, const char*); /* Compare using locale */ _CRTIMP char* __cdecl strcpy (char*, const char*); _CRTIMP size_t __cdecl strcspn (const char*, const char*) __MINGW_ATTRIB_PURE; _CRTIMP char* __cdecl strerror (int); /* NOTE: NOT an old name wrapper. */ _CRTIMP size_t __cdecl strlen (const char*) __MINGW_ATTRIB_PURE; _CRTIMP char* __cdecl strncat (char*, const char*, size_t); _CRTIMP int __cdecl strncmp (const char*, const char*, size_t) __MINGW_ATTRIB_PURE; _CRTIMP char* __cdecl strncpy (char*, const char*, size_t); _CRTIMP char* __cdecl strpbrk (const char*, const char*) __MINGW_ATTRIB_PURE; _CRTIMP char* __cdecl strrchr (const char*, int) __MINGW_ATTRIB_PURE; _CRTIMP size_t __cdecl strspn (const char*, const char*) __MINGW_ATTRIB_PURE; _CRTIMP char* __cdecl strstr (const char*, const char*) __MINGW_ATTRIB_PURE; _CRTIMP char* __cdecl strtok (char*, const char*); _CRTIMP size_t __cdecl strxfrm (char*, const char*, size_t); #ifndef __STRICT_ANSI__ /* * Extra non-ANSI functions provided by the CRTDLL library */ _CRTIMP char* __cdecl _strerror (const char *); _CRTIMP void* __cdecl _memccpy (void*, const void*, int, size_t); _CRTIMP int __cdecl _memicmp (const void*, const void*, size_t); _CRTIMP char* __cdecl _strdup (const char*) __MINGW_ATTRIB_MALLOC; _CRTIMP int __cdecl _strcmpi (const char*, const char*); _CRTIMP int __cdecl _stricmp (const char*, const char*); _CRTIMP int __cdecl _stricoll (const char*, const char*); _CRTIMP char* __cdecl _strlwr (char*); _CRTIMP int __cdecl _strnicmp (const char*, const char*, size_t); _CRTIMP char* __cdecl _strnset (char*, int, size_t); _CRTIMP char* __cdecl _strrev (char*); _CRTIMP char* __cdecl _strset (char*, int); _CRTIMP char* __cdecl _strupr (char*); _CRTIMP void __cdecl _swab (const char*, char*, size_t); #ifdef __MSVCRT__ _CRTIMP int __cdecl _strncoll(const char*, const char*, size_t); _CRTIMP int __cdecl _strnicoll(const char*, const char*, size_t); #endif #ifndef _NO_OLDNAMES /* * Non-underscored versions of non-ANSI functions. They live in liboldnames.a * and provide a little extra portability. Also a few extra UNIX-isms like * strcasecmp. */ _CRTIMP void* __cdecl memccpy (void*, const void*, int, size_t); _CRTIMP int __cdecl memicmp (const void*, const void*, size_t); _CRTIMP char* __cdecl strdup (const char*) __MINGW_ATTRIB_MALLOC; _CRTIMP int __cdecl strcmpi (const char*, const char*); _CRTIMP int __cdecl stricmp (const char*, const char*); __CRT_INLINE int __cdecl strcasecmp (const char * __sz1, const char * __sz2) {return _stricmp (__sz1, __sz2);} _CRTIMP int __cdecl stricoll (const char*, const char*); _CRTIMP char* __cdecl strlwr (char*); _CRTIMP int __cdecl strnicmp (const char*, const char*, size_t); __CRT_INLINE int __cdecl strncasecmp (const char * __sz1, const char * __sz2, size_t __sizeMaxCompare) {return _strnicmp (__sz1, __sz2, __sizeMaxCompare);} _CRTIMP char* __cdecl strnset (char*, int, size_t); _CRTIMP char* __cdecl strrev (char*); _CRTIMP char* __cdecl strset (char*, int); _CRTIMP char* __cdecl strupr (char*); #ifndef _UWIN _CRTIMP void __cdecl swab (const char*, char*, size_t); #endif /* _UWIN */ #endif /* _NO_OLDNAMES */ #endif /* Not __STRICT_ANSI__ */ #ifndef _WSTRING_DEFINED /* * Unicode versions of the standard calls. * Also in wchar.h, where they belong according to ISO standard. */ _CRTIMP wchar_t* __cdecl wcscat (wchar_t*, const wchar_t*); _CRTIMP wchar_t* __cdecl wcschr (const wchar_t*, wchar_t); _CRTIMP int __cdecl wcscmp (const wchar_t*, const wchar_t*); _CRTIMP int __cdecl wcscoll (const wchar_t*, const wchar_t*); _CRTIMP wchar_t* __cdecl wcscpy (wchar_t*, const wchar_t*); _CRTIMP size_t __cdecl wcscspn (const wchar_t*, const wchar_t*); /* Note: _wcserror requires __MSVCRT_VERSION__ >= 0x0700. */ _CRTIMP size_t __cdecl wcslen (const wchar_t*); _CRTIMP wchar_t* __cdecl wcsncat (wchar_t*, const wchar_t*, size_t); _CRTIMP int __cdecl wcsncmp(const wchar_t*, const wchar_t*, size_t); _CRTIMP wchar_t* __cdecl wcsncpy(wchar_t*, const wchar_t*, size_t); _CRTIMP wchar_t* __cdecl wcspbrk(const wchar_t*, const wchar_t*); _CRTIMP wchar_t* __cdecl wcsrchr(const wchar_t*, wchar_t); _CRTIMP size_t __cdecl wcsspn(const wchar_t*, const wchar_t*); _CRTIMP wchar_t* __cdecl wcsstr(const wchar_t*, const wchar_t*); _CRTIMP wchar_t* __cdecl wcstok(wchar_t*, const wchar_t*); _CRTIMP size_t __cdecl wcsxfrm(wchar_t*, const wchar_t*, size_t); #ifndef __STRICT_ANSI__ /* * Unicode versions of non-ANSI string functions provided by CRTDLL. */ /* NOTE: _wcscmpi not provided by CRTDLL, this define is for portability */ #define _wcscmpi _wcsicmp _CRTIMP wchar_t* __cdecl _wcsdup (const wchar_t*); _CRTIMP int __cdecl _wcsicmp (const wchar_t*, const wchar_t*); _CRTIMP int __cdecl _wcsicoll (const wchar_t*, const wchar_t*); _CRTIMP wchar_t* __cdecl _wcslwr (wchar_t*); _CRTIMP int __cdecl _wcsnicmp (const wchar_t*, const wchar_t*, size_t); _CRTIMP wchar_t* __cdecl _wcsnset (wchar_t*, wchar_t, size_t); _CRTIMP wchar_t* __cdecl _wcsrev (wchar_t*); _CRTIMP wchar_t* __cdecl _wcsset (wchar_t*, wchar_t); _CRTIMP wchar_t* __cdecl _wcsupr (wchar_t*); #ifdef __MSVCRT__ _CRTIMP int __cdecl _wcsncoll(const wchar_t*, const wchar_t*, size_t); _CRTIMP int __cdecl _wcsnicoll(const wchar_t*, const wchar_t*, size_t); #if __MSVCRT_VERSION__ >= 0x0700 _CRTIMP wchar_t* __cdecl _wcserror(int); _CRTIMP wchar_t* __cdecl __wcserror(const wchar_t*); #endif #endif #ifndef _NO_OLDNAMES /* NOTE: There is no _wcscmpi, but this is for compatibility. */ int __cdecl wcscmpi (const wchar_t * __ws1, const wchar_t * __ws2); __CRT_INLINE int __cdecl wcscmpi (const wchar_t * __ws1, const wchar_t * __ws2) {return _wcsicmp (__ws1, __ws2);} _CRTIMP wchar_t* __cdecl wcsdup (const wchar_t*); _CRTIMP int __cdecl wcsicmp (const wchar_t*, const wchar_t*); _CRTIMP int __cdecl wcsicoll (const wchar_t*, const wchar_t*); _CRTIMP wchar_t* __cdecl wcslwr (wchar_t*); _CRTIMP int __cdecl wcsnicmp (const wchar_t*, const wchar_t*, size_t); _CRTIMP wchar_t* __cdecl wcsnset (wchar_t*, wchar_t, size_t); _CRTIMP wchar_t* __cdecl wcsrev (wchar_t*); _CRTIMP wchar_t* __cdecl wcsset (wchar_t*, wchar_t); _CRTIMP wchar_t* __cdecl wcsupr (wchar_t*); #endif /* Not _NO_OLDNAMES */ #endif /* Not strict ANSI */ #define _WSTRING_DEFINED #endif /* _WSTRING_DEFINED */ #ifdef __cplusplus } #endif #endif /* Not RC_INVOKED */ #endif /* Not _STRING_H_ */ |