简单解决python安装中的Unable to find vcvarsall.bat问题

使用python36安装python的murmurhash的时候遇到上述问题，原因是没有找到vcvarsall.bat。查找vcvarsall.bat的方法是定义在_msvccompiler.py文件中的（注意该文件前面是有下划线的！），比如我本地的文件路径为"C:\Program Files\Python36\Lib\distutils\_msvccompiler.py“

打开该文件，修改函数_find_vcvarsall。我本地安装的是vs2017，vcvarsall.bat的路径为“E:\tools\vs2017\VC\Auxiliary\Build\vcvarsall.bat”

_find_vcvarsall的原文如下：

def _find_vcvarsall(plat_spec):
    try:
        key = winreg.OpenKeyEx(
            winreg.HKEY_LOCAL_MACHINE,
            r"Software\Microsoft\VisualStudio\SxS\VC7",
            access=winreg.KEY_READ | winreg.KEY_WOW64_32KEY
        )
    except OSError:
        log.debug("Visual C++ is not registered")
        return None, None

    with key:
        best_version = 0
        best_dir = None
        for i in count():
            try:
                v, vc_dir, vt = winreg.EnumValue(key, i)
            except OSError:
                break
            if v and vt == winreg.REG_SZ and os.path.isdir(vc_dir):
                try:
                    version = int(float(v))
                except (ValueError, TypeError):
                    continue
                if version >= 14 and version > best_version:
                    best_version, best_dir = version, vc_dir
        if not best_version:
            log.debug("No suitable Visual C++ version found")
            return None, None

        vcvarsall = os.path.join(best_dir, "vcvarsall.bat")
        if not os.path.isfile(vcvarsall):
            log.debug("%s cannot be found", vcvarsall)
            return None, None

        vcruntime = None
        vcruntime_spec = _VCVARS_PLAT_TO_VCRUNTIME_REDIST.get(plat_spec)
        if vcruntime_spec:
            vcruntime = os.path.join(best_dir,
                vcruntime_spec.format(best_version))
            if not os.path.isfile(vcruntime):
                log.debug("%s cannot be found", vcruntime)
                vcruntime = None

        return vcvarsall, vcruntime

修改为：

def _find_vcvarsall(plat_spec):
        best_dir = r'E:\tools\vs2017\VC\Auxiliary\Build'
        best_version = 17
        vcruntime = None
        vcruntime_spec = _VCVARS_PLAT_TO_VCRUNTIME_REDIST.get(plat_spec)
        if vcruntime_spec:
            vcruntime = os.path.join(best_dir,
                vcruntime_spec.format(best_version))
            if not os.path.isfile(vcruntime):
                log.debug("%s cannot be found", vcruntime)
                vcruntime = None
        print(vcruntime)
        return r'E:\tools\vs2017\VC\Auxiliary\Build\vcvarsall.bat', vcruntime

直接运行python安装即可。安装完后将该文件还原

如果遇到如下问题：

• 找不到cl.exe

解决方法：将cl.exe的路径加入到系统环境变量path即可

• mmh3module.cpp(9): error C2371: “int32_t”: 重定义；不同的基类型

解决办法：这个是因为int32_t的宏定义与其他地方重复，将mmh3module.cpp，murmur_hash_3.cpp，murmur_hash_3.hpp这三个文件中的int32_t全部替换为其他名称即可，比如int32_tA（或增加#ifndef判断），保存后重新安装