C语言 如何将目录添加到 C 头文件包含路径？
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How do I add a directory to C header include path?
提问by wdkrnls
I am having trouble installing a dependency for a program that itself depends on pcre.h. I have this installed to /opt/local/include, but the C compiler does not see it and thus gives me:
我在为本身依赖于 pcre.h 的程序安装依赖项时遇到问题。我将它安装到 /opt/local/include，但 C 编译器没有看到它，因此给了我：
error: pcre.h: No such file or directory
错误：pcre.h：没有那个文件或目录
I have confirmed this by writing a hello world program that tries to include it:
我已经通过编写一个试图包含它的 hello world 程序来确认这一点：
#include <pcre.h>
#include <stdio.h>
int main(void)
{
printf("hello, world\n");
return 0;
}
This also gives the error unless I specify the path as </opt/local/include/pcre.h>.
除非我将路径指定为</opt/local/include/pcre.h>.
I would like the C compiler to find this by default but I do not know where this is configured. Tab completion hasn't revealed any HEADER_PATHenvironment variables and I cannot find anything like it that isn't specific to XCode. I am, however, using Mac OSX Snow Leopard on the off chance that makes a difference.
我希望 C 编译器在默认情况下找到它，但我不知道这是在哪里配置的。选项卡完成没有显示任何HEADER_PATH环境变量，我找不到任何类似的东西不是特定于XCode 的。然而，我正在使用 Mac OSX Snow Leopard 的机会有所不同。
回答by R.. GitHub STOP HELPING ICE
Use -I /opt/local/includeon the command line or C_INCLUDE_PATH=/opt/local/includein the environment.
使用-I /opt/local/include在命令行或者C_INCLUDE_PATH=/opt/local/include在环境中。
回答by a paid nerd
Use the pcre-configutility to get the right flags:
使用该pcre-config实用程序获取正确的标志：
$ pcre-config --libs --cflags
-L/opt/local/lib -lpcre
-I/opt/local/include
If you're compiling via the command line,
如果您通过命令行编译，
$ gcc -Wall -g `pcre-config --libs --cflags` main.c
