std::filesystem::path::compare

 

C++

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技术规范

 

文件系统库

类
filesystem::path filesystem::filesystem_error filesystem::directory_entry filesystem::directory_iterator filesystem::recursive_directory_iterator filesystem::file_status	filesystem::space_info filesystem::file_type filesystem::perms filesystem::perm_options filesystem::copy_options filesystem::directory_options filesystem::file_time_type
函数
filesystem::absolute filesystem::canonicalfilesystem::weakly_canonical filesystem::relativefilesystem::proximate filesystem::copy filesystem::copy_file filesystem::copy_symlink filesystem::create_directory filesystem::create_directories filesystem::create_hard_link filesystem::create_symlink filesystem::create_directory_symlink filesystem::current_path	filesystem::exists filesystem::equivalent filesystem::file_size filesystem::hard_link_count filesystem::last_write_time filesystem::permissions filesystem::read_symlink filesystem::remove filesystem::remove_all filesystem::rename filesystem::resize_file filesystem::space filesystem::status filesystem::symlink_status filesystem::temp_directory_path
文件类型
filesystem::is_block_file filesystem::is_character_file filesystem::is_directory filesystem::is_empty filesystem::status_known	filesystem::is_fifo filesystem::is_other filesystem::is_regular_file filesystem::is_socket filesystem::is_symlink

 

std::filesystem::path

常量
path::native_formatpath::generic_formatpath::auto_format
成员函数
path::path path::~path path::operator= path::assign path::appendpath::operator /= path::concatpath::operator += path::clear path::make_preferred path::remove_filename path::replace_filename path::replace_extension path::swap path::compare path::beginpath::end	path::c_strpath::nativepath::operator string_type path::stringpath::u8stringpath::u16stringpath::u32stringpath::wstring path::generic_stringpath::generic_u8stringpath::generic_u16stringpath::generic_u32stringpath::generic_wstring path::lexically_normalpath::lexically_relativepath::lexically_proximate
路径分解
path::root_name path::root_directory path::root_path path::relative_path path::parent_path path::filename path::stem path::extension path::empty	path::has_root_pathpath::has_root_namepath::has_root_directorypath::has_relative_pathpath::has_parent_pathpath::has_filenamepath::has_stempath::has_extension path::is_absolutepath::is_relative
非成员函数
swap(path)
hash_value
operator==operator!=operator<operator<=operator>operator>=
operator/
operator<<operator>>
u8path

 

int compare( const path& p ) const noexcept;	(1)	(C++17 起)
int compare( const string_type& str ) const; int compare( std::basic_string_view<value_type> str ) const;	(2)	(C++17 起)
int compare( const value_type* s ) const;	(3)	(C++17 起)

比较 path 与另一 path 的字典表示。

1) 若 path 的原生表示（ native() ）以字典序小于、等于或大于 p 的原生表示（ p.native() ），则分别返回小于、等于或大于 0 的值。逐元素进行比较，如同通过在二个 path 上从 begin() 迭代到 end() 。

2) 等价于 compare(path(str)) 。

3) 等价于 compare(path(s)) 。

参数

p	-	要比较的 path
str	-	表示要比较的表示路径的字符串或字符串视图
s	-	表示要比较的路径的空终止字符串

返回值

若 path 的字典序小于给定 path 则为小于 0 的值。

若 path 的字典序等于给定 path 则为等于 0 的值。

若 path 的字典序大于给定 path 则为大于 0 的值。

异常

2-3) （无）

注意

对于双路比较，二元运算符可能更适合。

示例

运行此代码

#include <iostream>
#include <filesystem>
namespace fs = std::filesystem;
void demo(int rc, fs::path p1, fs::path p2) {
    if(rc < 0) std::cout << p1 << " < " << p2 << '\n';
    else if(rc > 0) std::cout << p1 << " > "  << p2 << '\n';
    else if(rc == 0) std::cout << p1 << "==" << p2 << '\n';
}
int main() {
    fs::path p1 = "/a/b/"; // 对于字典迭代如同 "a/b/."
    fs::path p2 = "/a/b/#";
    demo(p1.compare(p2), p1, p2);
    demo(p1.compare("a/b/_"), p1, "a/b/_");
}

输出：

"/a/b/" > "/a/b/#"
"/a/b/" < "a/b/_"

参阅

operator==operator!=operator<operator<=operator>operator>=

以字典序比较二个路径 (函数)