易于使用 Boost.Filesystem：create_directories

#include <boost/filesystem.hpp>
//...
boost::filesystem::create_directories("/tmp/a/b/c");

如果创建了新目录，则返回true，否则返回false。

在 C++ 17 或更高版本中，有一个带有函数std::filesystem::create_directories的标准头<filesystem>，应该在现代 C++ 程序中使用。

但是，这里有一个可以用 C ++ 编译器编译的 C 函数。

/*
@(#)File:           mkpath.c
@(#)Purpose:        Create all directories in path
@(#)Author:         J Leffler
@(#)Copyright:      (C) JLSS 1990-2020
@(#)Derivation:     mkpath.c 1.16 2020/06/19 15:08:10
*/
/*TABSTOP=4*/
#include "posixver.h"
#include "mkpath.h"
#include "emalloc.h"
#include <errno.h>
#include <string.h>
/* "sysstat.h" == <sys/stat.h> with fixup for (old) Windows - inc mode_t */
#include "sysstat.h"
typedef struct stat Stat;
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>
#include <unistd.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strdup()和free()的错误检查版本，在emalloc.h中声明（并在emalloc.c和estrdup.c中实现）。"sysstat.h"标题处理<sys/stat.h>的损坏版本

v1.12（答案的原始版本）和 v1.13（答案的修订版本）之间的变化是的，而不是中的，因为do_mkdir()中的是对EEXIST的测试；Switch指出这是必要的-谢谢，Switch。测试代码已

（特此允许您将此代码用于任何带有归因的目的。）

此代码在 GitHub 上的SOQ（堆栈溢出问题）存储库中作为src/so-0067-5039子目录中的文件mkpath.c和mkpath.h（等等）提供。

system("mkdir -p /tmp/a/b/c")

是我能想到的最短的方式 (就代码的长度而言,不一定是执行时间)。

它不是跨平台的，但将在 Linux 下工作。

这是我的代码示例（适用于 Windows 和 Linux）：

#include <iostream>
#include <string>
#include <sys/stat.h> // stat
#include <errno.h>    // errno, ENOENT, EEXIST
#if defined(_WIN32)
#include <direct.h>   // _mkdir
#endif
bool isDirExist(const std::string& path)
{
#if defined(_WIN32)
    struct _stat info;
    if (_stat(path.c_str(), &info) != 0)
    {
        return false;
    }
    return (info.st_mode & _S_IFDIR) != 0;
#else 
    struct stat info;
    if (stat(path.c_str(), &info) != 0)
    {
        return false;
    }
    return (info.st_mode & S_IFDIR) != 0;
#endif
}
bool makePath(const std::string& path)
{
#if defined(_WIN32)
    int ret = _mkdir(path.c_str());
#else
    mode_t mode = 0755;
    int ret = mkdir(path.c_str(), mode);
#endif
    if (ret == 0)
        return true;
    switch (errno)
    {
    case ENOENT:
        // parent didn't exist, try to create it
        {
            int pos = path.find_last_of('/');
            if (pos == std::string::npos)
#if defined(_WIN32)
                pos = path.find_last_of('\\');
            if (pos == std::string::npos)
#endif
                return false;
            if (!makePath( path.substr(0, pos) ))
                return false;
        }
        // now, try to create again
#if defined(_WIN32)
        return 0 == _mkdir(path.c_str());
#else 
        return 0 == mkdir(path.c_str(), mode);
#endif
    case EEXIST:
        // done!
        return isDirExist(path);
    default:
        return false;
    }
}
int main(int argc, char* ARGV[])
{
    for (int i=1; i<argc; i++)
    {
        std::cout << "creating " << ARGV[i] << " ... " << (makePath(ARGV[i]) ? "OK" : "failed") << std::endl;
    }
    return 0;
}

用法：

$ makePath 1/2 folderA/folderB/folderC
creating 1/2 ... OK
creating folderA/folderB/folderC ... OK