如何在C ++ / Linux中创建目录树？ [英] How can I create directory tree in C++/Linux?

问题描述

我想要一种在C ++ / Linux中创建多个目录的简单方法。

I want an easy way to create multiple directories in C++/Linux.

例如，我要在目录中保存一个文件lola.file：

For example I want to save a file lola.file in the directory:

/tmp/a/b/c

但是如果目录不在那里他们自动创建。一个工作示例是完美的。

but if the directories are not there I want them to be created automagically. A working example would be perfect.

推荐答案

这里是一个C函数，可以用C ++编译器编译。

Here's a C function that can be compiled with C++ compilers.

/*
@(#)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 = '\0';
            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 */

宏 STRDUP（）和 FREE（）是错误检查版本 strdup / code>中声明的和和 free（） c> emalloc.c 和 estrdup.c ）。 sysstat.h头处理< sys / stat.h> 的破坏版本，在现代Unix系统上（ c>< sys / stat.h> jlss.h声明 mkpath（）。

The macros STRDUP() and FREE() are error-checking versions of strdup() and free(), declared in emalloc.h (and implemented in emalloc.c and 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().

在v1.12（上一个）和v1.13（上面）之间的变化是 EEXIST 在中的测试do_mkdir（）。 切换—谢谢，开关。测试代码已经升级并在MacBook Pro（2.3GHz Intel Core i7，运行Mac OS X 10.7.4）上重现了这个问题，并建议问题在修订版本中修复（但测试只能显示错误的存在

The change between v1.12 (previous) and v1.13 (above) is the test for EEXIST in 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).

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