What function does Linux use to open a directory?

Use the opendir() function to open a directory in Linux. The opendir() function can open the specified directory and return a directory stream in the form of "DIR*". This return value must be used to read and search the specified directory; the syntax is "DIR * opendir(const char * name);" .

#The operating environment of this tutorial: linux7.3 system, Dell G3 computer.

linux opendir() function: open directory function

##1, header file:

#include <sys/types.h>   
#include <dirent.h>

2, define function

DIR * opendir(const char * name);

3, function description:

opendir() is used to open the directory specified by the parameter name, and return DIR * Directory stream in the form, similar to open(), this return value will be used for subsequent reading and searching of the directory.

4, return value:

If successful, a directory stream of type DIR* will be returned. If the opening fails, NULL will be returned.

5, error code:

• EACCESS Insufficient permissions .

• EMFILE The maximum number of files that a process can open simultaneously has been reached.

• ENFILE The maximum number of files that the system can open simultaneously has been reached.

• ENOTDIR parameter name is not a real directory.

• ENOENT The directory specified by parameter name does not exist, or the parameter name is an empty string.

• ENOMEM Out of core memory.

6, Example:

#include <sys/types.h>
#include <dirent.h>
#include <stdio.h>
int main()
{
        int a = opendir("/etc/passwd");
        printf("a = %d\n",a);
        return 0;
}

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