C/C++中，2个getline函数使用

C函数库中：

stdio.h

/* Like `getdelim', but reads up to a newline.

This function is not part of POSIX and therefore no official

cancellation point. But due to similarity with an POSIX interface

or due to the implementation it is a cancellation point and

therefore not marked with __THROW. */

extern _IO_ssize_t getline (char **__restrict __lineptr,

size_t *__restrict __n,

FILE *__restrict __stream) __wur;

该函数，用于读取文件。

C++函数库中：

iostream

/**

* @brief String extraction.

* @param s A character array in which to store the data.

* @param n Maximum number of characters to extract.

* @return *this

*

* Returns @c getline(s,n,widen('\n')).

*/

inline __istream_type&

getline(char_type* __s, streamsize __n)

{ return this->getline(__s, __n, this->widen('\n')); }

__istream_type&

getline(char_type* __s, streamsize __n, char_type __delim);

对比实例：

/*
* File:   main2.cpp
* Author: Vicky
*
* Created on 2011年11月25日, 上午10:16
*/

#include <iostream>
#include <stdio.h>
#include <cstring>
#include <stdlib.h>

/*
*
*/
int main(void) {
std::cout << "both getline the different ！" << std::endl;

int ret;
FILE* pf;
pf = fopen("./main.cpp", "r");
if (pf == NULL) {
perror("can not open file './main.cpp'");
return 1;
}

size_t size;
ssize_t read;
char* line;
line = (char*) malloc(64); // 如果分配太小的话，会出错
// 这个是stdio的getline
while ((read = getline(&line,&size,pf)) != EOF) {
std::cout << line << std::endl;
}
line = NULL;

std::cout << "inter something ，‘exit’！" << std::endl;

std::string str;
while (std::getline(std::cin,str) && str != "exit") {
std::cout << ">>" << str << std::endl;
}

ret = fclose(pf);
if (ret != 0) {
perror("can not close file './main.cpp'");
return 1;
}
return 0;
}

输出结果：

both getline the different ！
/*

* File:   main.cpp

* Author: Vicky

*

* Created on 2011年11月25日, 上午10:12

*/

#include <iostream>

#include <cstring>

/*

*

*/

int main(void) {

std::string str;

while (std::cin >> str && str != "exit") {

std::cout << str << std::endl;

}

return 0;

}

inter something ，‘exit’！
hello
>>hello
I'm vicky
>>I'm vicky
who are you?
>>who are you?
goodbye
>>goodbye
exit

运行成功（总计时间： 29s）