一、下载
官网下载地址：https://curl.haxx.se/download.html
选择最新的一个即可。
二、安装
1、解压
下载到的压缩包为curl-7.51.0.tar.gz，使用命令 tar -zxvf curl-7.51.0.tar.gz 解压。
2、进入解压出的目录curl-7.51.0，执行
（1）sudo ./configure
（2）sudo make
（3）sudo make install
安装完成，在命令行测试是否可用，直接输入curl，出现如下情况安装基本成功
如果提示该命令不存在。则执行以下命令：
export PATH=$PATH:/usr/local/curl/bin
检查/usr/include/里有没有crul没有的话，需要把解压出的include文件夹下的文件复制过去。
cp -r curl-7.51.0/include/curl/ /usr/include/
检查库和头文件
[root@localhost curl-7.51.0]# curl-config --cflags
-I/usr/local/include
[root@localhost curl-7.51.0]# curl-config --libs
-L/usr/local/lib -lcurl
以后使用gcc编译使用libcurl的c代码，都需加上-lcurl。
三、编译代码
使用libcurl官网的例子，只稍微修改。
/**********************************************
*
* Project CDRL
*
* Copyright (C) 1998 - 2015, Daniel Stenberg, <daniel@haxx.se>, et al.
*
* This software is licensed as described in the file COPYING, which
* you should have received as part of this distribution. The terms
* are also available at https://curl.haxx.se/docs/copyright.html.
*
* You may opt to use, copy, modify, merge, publish, distribute and/or sell
* copies of the Software, and permit persons to whom the Software is
* furnished to do so, under the terms of the COPYING file.
*
* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
* KIND, either express or implied.
*
**********************************************/
#include <stdio.h>
#include <curl/curl.h>
/* <DESC>
* Get a single file from an FTPS server.
* </DESC>
*/
struct FtpFile {
const char *filename;
FILE *stream;
};
static size_t my_fwrite(void *buffer, size_t size, size_t nmemb,void *stream)
{
struct FtpFile *out=(struct FtpFile *)stream;
if(out && !out->stream) {
/* open file for writing */
out->stream=fopen(out->filename, "wb");
if(!out->stream)
return -1; /* failure, can't open file to write */
}
return fwrite(buffer, size, nmemb, out->stream);
}
int main(void)
{
CURL *curl;
CURLcode res;
struct FtpFile ftpfile={
"yourfile.bin", /* name to store the file as if successful */
NULL
};
printf("come in");
return 0;
curl_global_init(CURL_GLOBAL_DEFAULT);
curl = curl_easy_init();
if(curl) {
/*
* You better replace the URL with one that works! Note that we use an
* FTP:// URL with standard explicit FTPS. You can also do FTPS:// URLs if
* you want to do the rarer kind of transfers: implicit.
*/
curl_easy_setopt(curl, CURLOPT_URL,"ftp://user@server/home/user/file.txt");
/* Define our callback to get called when there's data to be written */
curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, my_fwrite);
/* Set a pointer to our struct to pass to the callback */
curl_easy_setopt(curl, CURLOPT_WRITEDATA, &ftpfile);
/* We activate SSL and we require it for both control and data */
curl_easy_setopt(curl, CURLOPT_USE_SSL, CURLUSESSL_ALL);
/* Switch on full protocol/debug output */
curl_easy_setopt(curl, CURLOPT_VERBOSE, 1L);
res = curl_easy_perform(curl);
/* always cleanup */
curl_easy_cleanup(curl);
if(CURLE_OK != res) {
/* we failed */
fprintf(stderr, "curl told us %d\n", res);
}
}
if(ftpfile.stream)
fclose(ftpfile.stream); /* close the local file */
curl_global_cleanup();
return 0;
}
编译：gcc ftpsget.c -o ddd.out -lcurl
执行：
可能会出现的问题：error while loading shared libraries: libcurl.so.4: cannot open shared object file: No such file or directory
解决方法：
查找 libcurl所有相关的so库所在位置，在/etc/ld.so.conf中加入libcurl有关so库所在目录。
进入根目录/，执行find -name *libcurl.so*，就会发现所在目录。
在/etc/ld.so.conf中加入 /usr/local/lib 这一行。
保存/etc/ld.so.conf
执行命令 /sbin/ldconfig -v 生效。