Question

我想让我的C ++程序使用libcurl读取Web源代码，但它无法打开文件“curl.h”。

Answer 1

除非您已指示编译器在独立安装curl库的位置搜索标题，否则您可能正在寻找双引号，假设您已包含curl源。否则，您将需要在项目设置中摆弄包含路径。

What is the difference between #include <filename> and #include "filename"?

区别在于预处理器搜索包含文件的位置。

对于#include＆＃34; filename＆＃34;预处理器在与包含该指令的文件相同的目录中进行搜索，然后对#include进行搜索。此方法通常用于包含程序员定义的头文件。

对于#include＆lt;文件名＆gt;预处理器以依赖于实现的方式搜索，通常在编译器/ IDE预先指定的搜索目录中。此方法通常用于包含标准库头文件。

Answer 2

In short, 
Add the path of the libcurl's include folder in C/C++ -? General -> Additional include directories. This way the Visual Studio will get to know the location of curl.h

In Detail:
Using libcurl involves 2 steps:
1. Download and build libcurl on your platform.
2. Plug-it in your C\C++ application

Step 1: 
Download code from https://curl.haxx.se/download.html and unzip the zip file in a folder.  I guess you already have done it. 
cd curl-src\winbuild
nmake /f Makefile.vc mode=<static or dll>  <options>
VC=<6,7,8,9,10,11,12,14>     - VC versions
  WITH_DEVEL=<path>            - Paths for the development files (SSL, zlib, etc.)
                                 Defaults to sibbling directory deps: ../deps
                                 Libraries can be fetched at http://windows.php.net/downloads/php-sdk/deps/
                                 Uncompress them into the deps folder.
  WITH_SSL=<dll or static>     - Enable OpenSSL support, DLL or static
  WITH_MBEDTLS=<dll or static> - Enable mbedTLS support, DLL or static
  WITH_CARES=<dll or static>   - Enable c-ares support, DLL or static
  WITH_ZLIB=<dll or static>    - Enable zlib support, DLL or static
  WITH_SSH2=<dll or static>    - Enable libSSH2 support, DLL or static
  ENABLE_SSPI=<yes or no>      - Enable SSPI support, defaults to yes
  ENABLE_IPV6=<yes or no>      - Enable IPv6, defaults to yes
  ENABLE_IDN=<yes or no>       - Enable use of Windows IDN APIs, defaults to yes
                                 Requires Windows Vista or later, or installation from:
                                 https://www.microsoft.com/downloads/details.aspx?FamilyID=AD6158D7-DDBA-416A-9109-07607425A815
  ENABLE_WINSSL=<yes or no>    - Enable native Windows SSL support, defaults to yes
  GEN_PDB=<yes or no>          - Generate Program Database (debug symbols for release build)
  DEBUG=<yes or no>            - Debug builds
  MACHINE=<x86 or x64>         - Target architecture (default is x86)

For More info, you can read INSTALL file present in the downloaded zip.

Step 2: Once you have the library built, plug-it in you application as:
a) Right Click the VS project in which you want to add the dependency of curl and select properties.
b) Add the path of the libcurl's include folder in C/C++ -> General -> Additional include directories. This way the Visual Studio will get to know the location of curl.h
c) Add the path of libcurl library in linker -> General -> Additional  Library Directories. 
d) Mention libcurl name in Linker -> input -> Additional Dependencies. 

You are good to go ! 
Note: if you are using dll for curl, then this dll should be present in the same directory in which your .exe for the application is present.

如何将libcurl导入C ++项目？

2 个答案: