如何在 C++/Linux 中创建目录树？
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原文地址: http://stackoverflow.com/questions/675039/
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How can I create directory tree in C++/Linux?
提问by Lipis
I want an easy way to create multiple directories in C++/Linux.
我想要一种在 C++/Linux 中创建多个目录的简单方法。
For example I want to save a file lola.file in the directory:
例如我想在目录中保存一个文件 lola.file ：
/tmp/a/b/c
but if the directories are not there I want them to be created automagically. A working example would be perfect.
但如果目录不存在，我希望它们自动创建。一个工作示例将是完美的。
采纳答案by Jonathan Leffler
Here's a C function that can be compiled with C++ compilers.
这是一个可以用 C++ 编译器编译的 C 函数。
/*
@(#)File: $RCSfile: mkpath.c,v $
@(#)Version: $Revision: 1.13 $
@(#)Last changed: $Date: 2012/07/15 00:40:37 $
@(#)Purpose: Create all directories in path
@(#)Author: J Leffler
@(#)Copyright: (C) JLSS 1990-91,1997-98,2001,2005,2008,2012
*/
/*TABSTOP=4*/
#include "jlss.h"
#include "emalloc.h"
#include <errno.h>
#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif /* HAVE_UNISTD_H */
#include <string.h>
#include "sysstat.h" /* Fix up for Windows - inc mode_t */
typedef struct stat Stat;
#ifndef lint
/* Prevent over-aggressive optimizers from eliminating ID string */
const char jlss_id_mkpath_c[] = "@(#)$Id: mkpath.c,v 1.13 2012/07/15 00:40:37 jleffler Exp $";
#endif /* lint */
static int do_mkdir(const char *path, mode_t mode)
{
Stat st;
int status = 0;
if (stat(path, &st) != 0)
{
/* Directory does not exist. EEXIST for race condition */
if (mkdir(path, mode) != 0 && errno != EEXIST)
status = -1;
}
else if (!S_ISDIR(st.st_mode))
{
errno = ENOTDIR;
status = -1;
}
return(status);
}
/**
** mkpath - ensure all directories in path exist
** Algorithm takes the pessimistic view and works top-down to ensure
** each directory in path exists, rather than optimistically creating
** the last element and working backwards.
*/
int mkpath(const char *path, mode_t mode)
{
char *pp;
char *sp;
int status;
char *copypath = STRDUP(path);
status = 0;
pp = copypath;
while (status == 0 && (sp = strchr(pp, '/')) != 0)
{
if (sp != pp)
{
/* Neither root nor double slash in path */
*sp = 'system("mkdir -p /tmp/a/b/c")
';
status = do_mkdir(copypath, mode);
*sp = '/';
}
pp = sp + 1;
}
if (status == 0)
status = do_mkdir(path, mode);
FREE(copypath);
return (status);
}
#ifdef TEST
#include <stdio.h>
/*
** Stress test with parallel running of mkpath() function.
** Before the EEXIST test, code would fail.
** With the EEXIST test, code does not fail.
**
** Test shell script
** PREFIX=mkpath.$$
** NAME=./$PREFIX/sa/32/ad/13/23/13/12/13/sd/ds/ww/qq/ss/dd/zz/xx/dd/rr/ff/ff/ss/ss/ss/ss/ss/ss/ss/ss
** : ${MKPATH:=mkpath}
** ./$MKPATH $NAME &
** [...repeat a dozen times or so...]
** ./$MKPATH $NAME &
** wait
** rm -fr ./$PREFIX/
*/
int main(int argc, char **argv)
{
int i;
for (i = 1; i < argc; i++)
{
for (int j = 0; j < 20; j++)
{
if (fork() == 0)
{
int rc = mkpath(argv[i], 0777);
if (rc != 0)
fprintf(stderr, "%d: failed to create (%d: %s): %s\n",
(int)getpid(), errno, strerror(errno), argv[i]);
exit(rc == 0 ? EXIT_SUCCESS : EXIT_FAILURE);
}
}
int status;
int fail = 0;
while (wait(&status) != -1)
{
if (WEXITSTATUS(status) != 0)
fail = 1;
}
if (fail == 0)
printf("created: %s\n", argv[i]);
}
return(0);
}
#endif /* TEST */
The macros STRDUP()and FREE()are error-checking versions of strdup()and free(), declared in emalloc.h(and implemented in emalloc.cand estrdup.c). The "sysstat.h"header deals with broken versions of <sys/stat.h>and can be replaced by <sys/stat.h>on modern Unix systems (but there were many issues back in 1990). And "jlss.h"declares mkpath().
宏STRDUP()andFREE()是and的错误检查版本，在strdup()andfree()中声明emalloc.h（并在emalloc.cand 中实现estrdup.c）。该"sysstat.h"用的破碎版本头交易<sys/stat.h>，并且可以被替换为<sys/stat.h>现代Unix系统上（但也有许多问题在1990年）。并"jlss.h"声明mkpath()。
The change between v1.12 (previous) and v1.13 (above) is the test for EEXISTin do_mkdir(). This was pointed out as necessary by Switch— thank you, Switch. The test code has been upgraded and reproduced the problem on a MacBook Pro (2.3GHz Intel Core i7, running Mac OS X 10.7.4), and suggests that the problem is fixed in the revision (but testing can only show the presence of bugs, never their absence).
v1.12（以前）和 v1.13（上面）之间的变化是对EEXISTin的测试do_mkdir()。Switch指出这是必要的——谢谢你，Switch。测试代码已在MacBook Pro（2.3GHz Intel Core i7，运行Mac OS X 10.7.4）上升级并复现问题，并提示该问题已在修订版中修复（但测试只能显示存在错误，从不缺席）。
(You are hereby given permission to use this code for any purpose with attribution.)
（特此允许您出于任何目的使用此代码并注明出处。）
回答by ChristopheD
mkdir -p /dir/to/the/file
touch /dir/to/the/file/thefile.ending
is the shortest way I can think of (in terms of the length of code, not necessarily execution time).
是我能想到的最短方法（就代码长度而言，不一定是执行时间）。
It's not cross-platform but will work under Linux.
它不是跨平台的，但可以在 Linux 下工作。
回答by ChristopheD
#include <sys/types.h>
#include <sys/stat.h>
int status;
...
status = mkdir("/tmp/a/b/c", S_IRWXU | S_IRWXG | S_IROTH | S_IXOTH);
回答by Paul Tomblin
mkdir -p /tmp/a/{b,c}/d
From here. You may have to do separate mkdirs for /tmp, /tmp/a, /tmp/a/b/ and then /tmp/a/b/c because there isn't an equivalent of the -p flag in the C api. Be sure and ignore the EEXISTS errno while you're doing the upper level ones.
从这里开始。您可能必须为 /tmp、/tmp/a、/tmp/a/b/ 和 /tmp/a/b/c 分别执行单独的 mkdir，因为 C api 中没有与 -p 标志等效的标志。当你在做上层的时候，一定要忽略 EEXISTS errno。
回答by rmeador
The others got you the right answer, but I thought I'd demonstrate another neat thing you can do:
其他人给了你正确的答案，但我想我会展示你可以做的另一件事：
/tmp/a/b/d
/tmp/a/c/d
Will create the following paths:
将创建以下路径：
#include <boost/filesystem.hpp>
//...
boost::filesystem::create_directories("/tmp/a/b/c");
The braces allow you to create multiple directories at once on the same level of the hierarchy, whereas the -poption means "create parent directories as needed".
大括号允许您在层次结构的同一级别上一次创建多个目录，而该-p选项的意思是“根据需要创建父目录”。
回答by Jason Cohen
You said "C++" but everyone here seems to be thinking "Bash shell."
您说的是“C++”，但这里的每个人似乎都在考虑“Bash shell”。
Check out the source code to gnu mkdir; then you can see how to implement the shell commands in C++.
查看 gnu 的源代码mkdir；然后你可以看到如何在 C++ 中实现 shell 命令。
回答by Beno?t
Easy with Boost.Filesystem: create_directories
使用 Boost.Filesystem 很容易： create_directories
bool mkpath( std::string path )
{
bool bSuccess = false;
int nRC = ::mkdir( path.c_str(), 0775 );
if( nRC == -1 )
{
switch( errno )
{
case ENOENT:
//parent didn't exist, try to create it
if( mkpath( path.substr(0, path.find_last_of('/')) ) )
//Now, try to create again.
bSuccess = 0 == ::mkdir( path.c_str(), 0775 );
else
bSuccess = false;
break;
case EEXIST:
//Done!
bSuccess = true;
break;
default:
bSuccess = false;
break;
}
}
else
bSuccess = true;
return bSuccess;
}
Returns: trueif a new directory was created, otherwise false.
返回：true如果创建了新目录，否则false.
回答by Mark
#include <iostream>
#include <string>
#include <sys/stat.h>
int
mkpath(std::string s,mode_t mode)
{
size_t pos=0;
std::string dir;
int mdret;
if(s[s.size()-1]!='/'){
// force trailing / so we can handle everything in loop
s+='/';
}
while((pos=s.find_first_of('/',pos))!=std::string::npos){
dir=s.substr(0,pos++);
if(dir.size()==0) continue; // if leading / first time is 0 length
if((mdret=mkdir(dir.c_str(),mode)) && errno!=EEXIST){
return mdret;
}
}
return mdret;
}
int main()
{
int mkdirretval;
mkdirretval=mkpath("./foo/bar",0755);
std::cout << mkdirretval << '\n';
}
回答by phorgan1
This is similar to the previous but works forward through the string instead of recursively backwards. Leaves errno with the right value for last failure. If there's a leading slash, there's an extra time through the loop which could have been avoided via one find_first_of() outside the loop or by detecting the leading / and setting pre to 1. The efficiency is the same whether we get set up by a first loop or a pre loop call, and the complexity would be (slightly) higher when using the pre-loop call.
这与前面的类似，但通过字符串向前工作，而不是向后递归。将 errno 保留为上次失败的正确值。如果有前导斜杠，则循环中会有额外的时间，这可以通过循环外的 find_first_of() 或通过检测前导 / 并将 pre 设置为 1 来避免。第一个循环或预循环调用，使用预循环调用时复杂性会（略）高。
c:\foo\bar\hello\world
回答by Andy
Since this post is ranking high in Google for "Create Directory Tree", I am going to post an answer that will work for Windows — this will work using Win32 API compiled for UNICODE or MBCS. This is ported from Mark's code above.
由于这篇文章在 Google 的“创建目录树”中排名靠前，我将发布一个适用于 Windows 的答案——这将使用为 UNICODE 或 MBCS 编译的 Win32 API 工作。这是从上面 Mark 的代码移植过来的。
Since this is Windows we are working with, directory separators are BACK-slashes, not forward slashes. If you would rather have forward slashes, change '\\'to '/'
由于这是我们正在使用的 Windows，目录分隔符是反斜杠，而不是正斜杠。如果您希望使用正斜杠，请更改'\\'为'/'
It will work with:
它将与：
c:\foo\bar\hellp\world\
and
和
bool CreateDirectoryTree(LPCTSTR szPathTree, LPSECURITY_ATTRIBUTES lpSecurityAttributes = NULL){
bool bSuccess = false;
const BOOL bCD = CreateDirectory(szPathTree, lpSecurityAttributes);
DWORD dwLastError = 0;
if(!bCD){
dwLastError = GetLastError();
}else{
return true;
}
switch(dwLastError){
case ERROR_ALREADY_EXISTS:
bSuccess = true;
break;
case ERROR_PATH_NOT_FOUND:
{
TCHAR szPrev[MAX_PATH] = {0};
LPCTSTR szLast = _tcsrchr(szPathTree,'\');
_tcsnccpy(szPrev,szPathTree,(int)(szLast-szPathTree));
if(CreateDirectoryTree(szPrev,lpSecurityAttributes)){
bSuccess = CreateDirectory(szPathTree,lpSecurityAttributes)!=0;
if(!bSuccess){
bSuccess = (GetLastError()==ERROR_ALREADY_EXISTS);
}
}else{
bSuccess = false;
}
}
break;
default:
bSuccess = false;
break;
}
return bSuccess;
}
(i.e.: does not need trailing slash, so you don't have to check for it.)
（即：不需要尾部斜杠，因此您不必检查它。）
Before saying "Just use SHCreateDirectoryEx()in Windows", note that SHCreateDirectoryEx()is deprecated and could be removed at any time from future versions of Windows.
在说“在 Windows 中只使用SHCreateDirectoryEx()”之前，请注意SHCreateDirectoryEx()已被弃用，并且可以随时从 Windows 的未来版本中删除。
##代码##