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Full Discussion: Function open() sets errno
Top Forums Programming Function open() sets errno Post 302826993 by DGPickett on Thursday 27th of June 2013 05:10:58 PM
Old 06-27-2013
Well open() returns an integer, which if -1 means errno is set to tell you what you did wrong. It sounds like your access in not good. You can set errno to zero before and test afterward. The nature of errno is that it is only set for errors, not reset on success. I usually:
Code:
if ( 0 > ( fd = open( file_name_ptr, O_RDONLY ))){
    perror( file_name_ptr );
    exit( 1 );
  }

This User Gave Thanks to DGPickett For This Post:
 

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OPENDIR(3)						     Linux Programmer's Manual							OPENDIR(3)

NAME
opendir - open a directory SYNOPSIS
#include <sys/types.h> #include <dirent.h> DIR *opendir(const char *name); DESCRIPTION
The opendir() function opens a directory stream corresponding to the directory name, and returns a pointer to the directory stream. The stream is positioned at the first entry in the directory. RETURN VALUE
The opendir() function returns a pointer to the directory stream or NULL if an error occurred. ERRORS
EACCES Permission denied. EMFILE Too many file descriptors in use by process. ENFILE Too many files are currently open in the system. ENOENT Directory does not exist, or name is an empty string. ENOMEM Insufficient memory to complete the operation. ENOTDIR name is not a directory. NOTES
The underlying file descriptor of the directory stream can be obtained using dirfd(3). CONFORMING TO
SVID 3, POSIX, BSD 4.3 SEE ALSO
open(2), closedir(3), dirfd(3), readdir(3), rewinddir(3), scandir(3), seekdir(3), telldir(3) 1995-06-11 OPENDIR(3)
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