memcpy Copy block of memory Copies the values of num bytes from the location pointed to by source directly to the memory block pointed to by destination. The underlying type of the objects pointed to by both the source and destination pointers are ir…

C 标准库 - string.h This header file defines several functions to manipulate C strings and arrays. string .h 头文件定义了一个变量类型.一个宏和各种操作字符数组的函数. 库变量 size_t Unsigned integral type (type ) 这是无符号整数类型,它是 sizeof 关键字的结果. 库宏 NULL Null pointer 这个宏是一个空指针常量的值. 库函数 void…

本文地址:http://www.cnblogs.com/archimedes/p/c-library-string.html,转载请注明源地址. 1.背景知识 <string.h>中声明的函数是对标准C的一个重要补充,它们支持C语言把文本作为字符数组操作的传统. string.h是C语言中C标准库的头文件,其中包含了宏定义.常量以及函数和类型的声明,涉及的内容除了字符串处理之外,还包括大量的内存处理函数:因此,string.h这个命名是不恰当的.在string.h中定义的函数十分常用,作为C标…

strlen 计算字符串长度 size_t strlen(const char *str) 计算字符串 str 的长度,直到空结束字符,但不包括空结束字符. 函数实现: int Strlen(const char *str) { assert(str); int len = 0; while ((*str++) != '\0')len++; return len; } strcpy 字符串复制 char *strcpy(char *dest, const char *src) 把 src 所指向…

memmove Move block of memory Copies the values of num bytes from the location pointed by source to the memory block pointed by destination. Copying takes place as if an intermediate buffer were used, allowing the destination and source to overlap. Th…

memcmp Compare two blocks of memory. Compares the first num bytes of the block of memory pointed by ptr1 to the first num bytes pointed by ptr2, returning zero if they all match or a value different from zero representing which is greater if they do…

memchr Locate character in block of memory,Searches within the first num bytes of the block of memory pointed by ptr for the first occurrence of ch (interpreted as an unsigned char), and returns a pointer to it. 在参数 ptr 所指向的字符串的前 count 个字节中搜索第一次出现字符…

strlen Returns the length of the C string str. The length of a C string is determined by the terminating null-character: A C string is as long as the number of characters between the beginning of the string and the terminating null character (without…

strpbrk Locate characters in string,Returns a pointer to the first occurrence in str1 of any of the characters that are part of str2, or a null pointer if there are no matches. The search does not include the terminating null-characters of either str…

strrchr Locate last occurrence of character in string, Returns a pointer to the last occurrence of character in the C string str. The terminating null-character is considered part of the C string. Therefore, it can also be located to retrieve a point…