当我使用 gcc 编译一个非常简单的源文件时，我不必指定标准包含文件（例如 stdio 或 stdlib）的路径。
GCC 如何知道如何找到这些文件？
它是否有/usr/include内部硬连线的路径，或者它会从其他操作系统组件获取路径？
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5 回答
241
为了弄清楚gcc/使用的默认路径g++以及它们的优先级，您需要检查以下命令的输出：
- 对于C：
gcc -xc -E -v -
- 对于C++：
gcc -xc++ -E -v -
功劳归于Qt Creator 团队。
于 2011-07-12T15:01:01.053 回答
50
有一个输出较短的命令，它允许自动从行中剪切包含路径，从一个空格开始：
$ echo | gcc -Wp,-v -x c++ - -fsyntax-only
ignoring nonexistent directory "/usr/lib/gcc/x86_64-redhat-linux/4.8.2/include-fixed"
ignoring nonexistent directory "/usr/lib/gcc/x86_64-redhat-linux/4.8.2/../../../../x86_64-redhat-linux/include"
#include "..." search starts here:
#include <...> search starts here:
/usr/lib/gcc/x86_64-redhat-linux/4.8.2/../../../../include/c++/4.8.2
/usr/lib/gcc/x86_64-redhat-linux/4.8.2/../../../../include/c++/4.8.2/x86_64-redhat-linux
/usr/lib/gcc/x86_64-redhat-linux/4.8.2/../../../../include/c++/4.8.2/backward
/usr/lib/gcc/x86_64-redhat-linux/4.8.2/include
/usr/local/include
/usr/include
End of search list.
功劳归于 libc++头版。
于 2013-11-07T15:34:26.380 回答
2
尽管我同意 Ihor Kaharlichenko 关于考虑 C++ 的回答以及 abyss.7 关于其输出紧凑性的回答，但对于 gcc 的多架构版本，它们仍然不完整，因为输入处理取决于命令行参数和宏。
例子：
echo | /opt/gcc-arm-none-eabi-9-2019-q4-major/bin/arm-none-eabi-g++ -specs=nano.specs -mcpu=cortex-m4 -march=armv7e-m -mthumb -mfloat-abi=soft -x c++ -E -Wp,-v\
- -fsyntax-only产量
⋮
/opt/gcc-arm-none-eabi-9-2019-q4-major/bin/../arm-none-eabi/include/newlib-nano
/opt/gcc-arm-none-eabi-9-2019-q4-major/bin/../lib/gcc/arm-none-eabi/9.2.1/../../../../arm-none-eabi/include/c++/9.2.1
/opt/gcc-arm-none-eabi-9-2019-q4-major/bin/../lib/gcc/arm-none-eabi/9.2.1/../../../../arm-none-eabi/include/c++/9.2.1/arm-none-eabi/thumb/v7e-m/nofp
/opt/gcc-arm-none-eabi-9-2019-q4-major/bin/../lib/gcc/arm-none-eabi/9.2.1/../../../../arm-none-eabi/include/c++/9.2.1/backward
/opt/gcc-arm-none-eabi-9-2019-q4-major/bin/../lib/gcc/arm-none-eabi/9.2.1/include
/opt/gcc-arm-none-eabi-9-2019-q4-major/bin/../lib/gcc/arm-none-eabi/9.2.1/include-fixed
/opt/gcc-arm-none-eabi-9-2019-q4-major/bin/../lib/gcc/arm-none-eabi/9.2.1/../../../../arm-none-eabi/include
⋮
而echo | /opt/gcc-arm-none-eabi-9-2019-q4-major/bin/arm-none-eabi-g++ -x c++ -E -Wp,-v - -fsyntax-only产量
⋮
/opt/gcc-arm-none-eabi-9-2019-q4-major/bin/../lib/gcc/arm-none-eabi/9.2.1/../../../../arm-none-eabi/include/c++/9.2.1
/opt/gcc-arm-none-eabi-9-2019-q4-major/bin/../lib/gcc/arm-none-eabi/9.2.1/../../../../arm-none-eabi/include/c++/9.2.1/arm-none-eabi
/opt/gcc-arm-none-eabi-9-2019-q4-major/bin/../lib/gcc/arm-none-eabi/9.2.1/../../../../arm-none-eabi/include/c++/9.2.1/backward
/opt/gcc-arm-none-eabi-9-2019-q4-major/bin/../lib/gcc/arm-none-eabi/9.2.1/include
/opt/gcc-arm-none-eabi-9-2019-q4-major/bin/../lib/gcc/arm-none-eabi/9.2.1/include-fixed
/opt/gcc-arm-none-eabi-9-2019-q4-major/bin/../lib/gcc/arm-none-eabi/9.2.1/../../../../arm-none-eabi/include
⋮
前一个调用使用newlib（参见输出的第 1 行和第 3 行），后者与标准包含一起使用。列表末尾的常用文件是include_next.
底线：打印包含目录时始终考虑所有宏和编译器选项。
于 2019-11-27T10:34:17.937 回答
0
总结其他答案：
对于 C++：
c++ -xc++ /dev/null -E -Wp,-v 2>&1 | sed -n 's,^ ,,p'
对于 C：
cc -xc /dev/null -E -Wp,-v 2>&1 | sed -n 's,^ ,,p'
于 2022-01-07T23:40:50.643 回答
0
只需运行以下命令即可列出默认搜索路径：
$(gcc -print-prog-name=cc1) -v
于 2019-06-18T08:17:26.090 回答