c++判断文件是否存在的方法汇总

#include <sys/stat.h>
#include <unistd.h>
#include <string>
#include <fstream>
inline bool exists_test0 (const std::string& name) {
    ifstream f(name.c_str());
    return f.good();
}
inline bool exists_test1 (const std::string& name) {
    if (FILE *file = fopen(name.c_str(), "r")) {
        fclose(file);
        return true;
    } else {
        return false;
    }   
}
inline bool exists_test2 (const std::string& name) {
    return ( access( name.c_str(), F_OK ) != -1 );
}
inline bool exists_test3 (const std::string& name) {
  struct stat buffer;   
  return (stat (name.c_str(), &buffer) == 0); 
}

# Results for total time to run the 100,000 calls averaged over 5 runs,
Method exists_test0 (ifstream): **0.485s**
Method exists_test1 (FILE fopen): **0.302s**
Method exists_test2 (posix access()): **0.202s**
Method exists_test3 (posix stat()): **0.134s**

bool IsFileExistent(const boost::filesystem::path& path) {
    boost::system:error_code error;
    return boost::filesystem::is_regular_file(path, error);
}

bool IsFileExistent(const boost::filesystem::path& path) {
    boost::system:error_code error;
    auto file_status = boost::filesystem::status(path, error);
    if (error) {
        return false;
    }
    if (! boost::filesystem::exists(file_status)) {
        return false;
    }
    if (boost::filesystem::is_directory(file_status)) {
        return false;
    }
    return true;
}

GetFileAttributes( m_Output) == -1 //判断文件是否存在若不存在返回-1

ULONGLONG size;
CFileStatus fileStatus;
//文件绝对路径
if (CFile::GetStatus(m_Output, fileStatus))
size = fileStatus.m_size;