使用libgit2共享库编译C项目时遇uint8_t未知类型错误求助

环境与编译尝试 #

在GitHub Codespaces、Windows、MacOS X Ventura环境下，先后尝试以下编译命令：

命令1（gcc-13） #

gcc-13 -L./libgit2-1.6.4/build -I./libgit2-1.6.4/include/git2 main.c ini.c

出现错误：

In file included from /Library/Developer/CommandLineTools/SDKs/MacOSX13.sdk/usr/include/sys/wait.h:110,
from /Library/Developer/CommandLineTools/SDKs/MacOSX13.sdk/usr/include/stdlib.h:66,
from main.c:3:
/Library/Developer/CommandLineTools/SDKs/MacOSX13.sdk/usr/include/sys/resource.h:203:9: error: unknown type name 'uint8_t'
203 | uint8_t ri_uuid[16];
| ^~~~~~~
/Library/Developer/CommandLineTools/SDKs/MacOSX13.sdk/usr/include/sys/resource.h:204:9: error: ...

命令2（clang） #

clang -L./libgit2-1.6.4/build -I./libgit2-1.6.4/include/git2 -I./inih-r56 main.c

出现类似错误：

In file included from main.c:3:
In file included from /Library/Developer/CommandLineTools/SDKs/MacOSX.sdk/usr/include/stdlib.h:66:
In file included from /Library/Developer/CommandLineTools/SDKs/MacOSX.sdk/usr/include/sys/wait.h:110:
/Library/Developer/CommandLineTools/SDKs/MacOSX.sdk/usr/include/sys/resource.h:203:2: error: unknown type name 'uint8_t'
uint8_t ri_uuid[16];
^
/Library/Developer/CommandLineTools/SDKs/MacOSX.sdk/usr/include/sys/resource.h:204:2: error: unknown type name 'uint64_t'
uint64_t ri_user_time;
^
.....

项目目录结构 #

├── inih-r56
│   ├── LICENSE.txt
│   ├── README.md
│   ├── cpp
│   ├── examples
│   ├── fuzzing
│   ├── ini.c
│   ├── ini.h
│   ├── meson.build
│   ├── meson_options.txt
│   └── tests
├── libgit2-1.6.4
│   ├── AUTHORS
│   ├── CMakeLists.txt
│   ├── COPYING
│   ├── README.md
│   ├── SECURITY.md
│   ├── api.docurium
│   ├── build
│   ├── ci
│   ├── cmake
│   ├── deps
│   ├── docs
│   ├── examples
│   ├── fuzzers
│   ├── git.git-authors
│   ├── include
│   ├── package.json
│   ├── script
│   ├── src
│   └── tests
└── main.c

libgit2 build目录结构 #

├── CMakeCache.txt
├── CMakeFiles
│   ├── 3.26.3
│   ├── CMakeConfigureLog.yaml
│   ├── CMakeDirectoryInformation.cmake
│   ├── CMakeRuleHashes.txt
│   ├── CMakeScratch
│   ├── Makefile.cmake
│   ├── Makefile2
│   ├── TargetDirectories.txt
│   ├── cmake.check_cache
│   ├── pkgRedirects
│   └── progress.marks
├── CTestTestfile.cmake
├── Makefile
├── cmake_install.cmake
├── deps
│   ├── http-parser
│   └── ntlmclient
├── include
│   ├── git2
│   └── git2.h
├── libgit2.pc
├── src
│   ├── CMakeFiles
│   ├── Makefile
│   ├── cli
│   ├── cmake_install.cmake
│   ├── libgit2
│   └── util
└── tests
    ├── CMakeFiles
    ├── CTestTestfile.cmake
    ├── Makefile
    ├── cmake_install.cmake
    ├── headertest
    ├── libgit2
    └── util

问题分析与解决办法 #

错误核心是uint8_t/uint64_t等固定宽度整数类型未被定义，这类类型属于C99标准，需确保编译环境正确引入相关定义：

1. 调整头文件包含顺序
   在main.c最开头先包含<stdint.h>，确保系统头文件引用前已定义类型：

   #include <stdint.h>
   #include <stdlib.h>
   // 其他头文件...
   

2. 指定C标准并补全链接参数
   编译命令添加-std=c99指定C99标准，同时修正头文件路径（libgit2头文件需通过git2/xxx.h引用，应包含上级目录），并加上-lgit2链接库：

   gcc-13 -std=c99 -L./libgit2-1.6.4/build -I./libgit2-1.6.4/include -I./inih-r56 main.c ini.c -lgit2
   

3. 重新配置libgit2编译
   进入libgit2-1.6.4/build目录，重新指定C标准编译libgit2：

   cmake .. -DCMAKE_C_STANDARD=99
   make clean && make
   

4. MacOS环境修复
   更新Xcode Command Line Tools到最新版本，解决SDK头文件兼容性问题：

   xcode-select --install
   

内容的提问来源于stack exchange，提问作者Chaitanya Sharma