C Standard Library – <string.h>

May 11, 2021 C

1. C Standard Library - slt;string.h>

2. Brief introduction

3. Library variables

4. Library macros

5. The library function

C Standard Library - slt;string.h>

Brief introduction

The string .h header file defines a function of a variable type, a macro, and an array of various operational characters.

Library variables

Here are the types of variables defined in the header file string.h:

Serial number	Variable & description
1	size_t This is an unsigned integer type, it is sizeof The result of the keyword.

Library macros

Here are the macros defined in the header file string.h:

Serial number	Macro & Description
1	NULL This macro is a value of an empty pointer.

The library function

Here are the functions defined in the header file string.h:

Serial number	Function & Description
1	void memchr(const void str, int c, size_t n) Parameter str Search for the first time C (an unsigned character) in the first N byte of the string pointed to.
2	int memcmp(const void str1, const void str2, size_t n) Bundle str1 with str2 The first N bytes are compared.
3	void memcpy(void dest, const void src, size_t n) Copy n characters from SRC to dest* 。
4	void memmove(void dest, const void src, size_t n) Another str2* Copy n characters to str1 The function.
5	void memset(void str, int c, size_t n) Copy Character C (A Non-symbolic character) to parameters str The first n characters of the polar string pointed to.
6	char strcat(char dest, const char src) Bundle src* The string pointed to dest The end of the string pointed to.
7	char strncat(char dest, const char src, size_t n) Bundle src* The string pointed to dest The end of the string pointing until the N-character length.
8	char strchr(const char str, int c) Parameter str Search in the character string to search for the first time character c (a unsigned character) position.
9	int strcmp(const char str1, const char str2) Bundle str1 The string pointed to str2 The point to the string is compared.
10	int strncmp(const char str1, const char str2, size_t n) Bundle str1 with str2 Compare, up to the previous N bytes.
11	int strcoll(const char str1, const char str2) Bundle str1 with str2 Comparison, the result depends on the location setting of LC_COLLATE.
12	char strcpy(char dest, const char src) Bundle src* Copy the string pointed to dest 。
13	char strncpy(char dest, const char src, size_t n) Bundle src* Copy the string pointed to dest Copy N characters up to.
14	size_t strcspn(const char str1, const char str2) Retrieving string STR1 does not contain characters in string STR2 in a row.
15	char *strerror(int errnum) Search for error number errnum from the internal array and returns a pointer to the error message string.
16	size_t strlen(const char *str) Calculate the length of the string STR until the empty end character, but does not include empty end characters.
17	char strpbrk(const char str1, const char str2) Retrieve string str1* The first matching string str2 The characters of the Chinese characters do not include empty end characters.That is, the characters in the string STR1 are verified in turn, and when the character is also included in the string STR2, the test is stopped and the character position is returned.
18	char strrchr(const char str, int c) Parameter str Search in the character string in the point to search for the last appearance character C (a unsigned character) position.
19	size_t strspn(const char str1, const char str2) Retrieve string str1 The first one is not in the string str2 The characters that appear in the middle.
20	char strstr(const char haystack, const char needle) String haystack* Find the first string needle (Do not include empty end characters).
21	char strtok(char str, const char delim) Decomposition string str* For a set of strings, delim Separator.
22	size_t strxfrm(char dest, const char src, size_t n) Convert strings based on LC_COLLLATE in the current area option src Before n Character and place them in strings dest middle.

Serial number	Function & Description
1	void memchr(const void str, int c, size_t n) Parameter str Search for the first time C (an unsigned character) in the first N byte of the string pointed to.
2	int memcmp(const void str1, const void str2, size_t n) Bundle str1 with str2 The first N bytes are compared.
3	void memcpy(void dest, const void src, size_t n) Copy n characters from SRC to dest* 。
4	void memmove(void dest, const void src, size_t n) Another str2* Copy n characters to str1 The function.
5	void memset(void str, int c, size_t n) Copy Character C (A Non-symbolic character) to parameters str The first n characters of the polar string pointed to.
6	char strcat(char dest, const char src) Bundle src* The string pointed to dest The end of the string pointed to.
7	char strncat(char dest, const char src, size_t n) Bundle src* The string pointed to dest The end of the string pointing until the N-character length.
8	char strchr(const char str, int c) Parameter str Search in the character string to search for the first time character c (a unsigned character) position.
9	int strcmp(const char str1, const char str2) Bundle str1 The string pointed to str2 The point to the string is compared.
10	int strncmp(const char str1, const char str2, size_t n) Bundle str1 with str2 Compare, up to the previous N bytes.
11	int strcoll(const char str1, const char str2) Bundle str1 with str2 Comparison, the result depends on the location setting of LC_COLLATE.
12	char strcpy(char dest, const char src) Bundle src* Copy the string pointed to dest 。
13	char strncpy(char dest, const char src, size_t n) Bundle src* Copy the string pointed to dest Copy N characters up to.
14	size_t strcspn(const char str1, const char str2) Retrieving string STR1 does not contain characters in string STR2 in a row.
15	char *strerror(int errnum) Search for error number errnum from the internal array and returns a pointer to the error message string.
16	size_t strlen(const char *str) Calculate the length of the string STR until the empty end character, but does not include empty end characters.
17	char strpbrk(const char str1, const char str2) Retrieve string str1* The first matching string str2 The characters of the Chinese characters do not include empty end characters.That is, the characters in the string STR1 are verified in turn, and when the character is also included in the string STR2, the test is stopped and the character position is returned.
18	char strrchr(const char str, int c) Parameter str Search in the character string in the point to search for the last appearance character C (a unsigned character) position.
19	size_t strspn(const char str1, const char str2) Retrieve string str1 The first one is not in the string str2 The characters that appear in the middle.
20	char strstr(const char haystack, const char needle) String haystack* Find the first string needle (Do not include empty end characters).
21	char strtok(char str, const char delim) Decomposition string str* For a set of strings, delim Separator.
22	size_t strxfrm(char dest, const char src, size_t n) Convert strings based on LC_COLLLATE in the current area option src Before n Character and place them in strings dest middle.