Name

Library

Synopsis

Return values

Detailed description

The data in the buffer is a series of dirent structures each containing the following entries:

u_int32_t d_fileno;
u_int16_t d_reclen;
u_int8_t  d_type;
u_int8_t  d_namlen;
char      d_name[MAXNAMELEN + 1];       /* see below */

         

The d_fileno entry is a number which is unique for each distinct file in the file system. Files that are linked by hard links (see link) have the same d_fileno. The d_reclen entry is the length, in bytes, of the directory record. The d_type entry is the type of the file pointed to by the directory record. The file type values are defined in <sys/dirent.h>. Presently, file type is not supported. d_type entry is set to 0. The d_name entry contains a null terminated file name. The d_namlen entry specifies the length of the file name excluding the null byte. Thus the actual size of d_name may vary from 1 to MAXNAMELEN + 1.

Entries may be separated by extra space. The d_reclen entry may be used as an offset from the start of a dirent structure to the next structure, if any.

The actual number of bytes transferred is returned. The current position pointer associated with fd is set to point to the next block of entries. The pointer may not advance by the number of bytes returned by getdirentries A value of zero is returned when the end of the directory has been reached.

The getdirentries system call writes the position of the block read into the location pointed to by basep. Alternatively, the current position pointer may be set and retrieved by lseek. The current position pointer should only be set to a value returned by lseek, a value returned in the location pointed to by basep ( (getdirentries);
only) or zero.

Examples

/****************** reading directory stream using getdirenttries *******************/
/****************** considering directory c:    emp already exists ********************/
#include <stdio.h>
int main()
{
        int retval;
        long basep=(off_t) 0;
        char buf[1024];
        struct dirent * d;
        char * dname="C:\       emp\
        char * fname="C:\       emp\\input.txt";
        int fd,fd1;
        fd1=open(fname,O_WRONLY|O_CREAT);
        if(fd==-1)
                {
                printf("file creation failed\n");
                return -1;
                }
        fd=open(dname,O_RDONLY);
        if(fd==-1)
                {
                printf("directory opening failed\n");
                return -1;
                }
        retval = getdirentries (fd, buf,(unsigned int)sizeof (buf),&basep);
        if(retval == -1)
        {
                printf("getdirentries call failed\n");
                return -1;
        }               
       
        d=(struct dirent *)buf;
        
        printf("name of the file in the newly created directory is \"%s\"\n",d-d_name);
        
        close(fd1);
        close(fd);
        return 0;
}

         

Output

name of the file in the newly created directory is "input.txt"

         

Errors

See also

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