redhat man page for euidaccess

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

NAME
       euidaccess, eaccess - check effective user's permissions for a file

SYNOPSIS
       #define _GNU_SOURCE	       /* See feature_test_macros(7) */
       #include <unistd.h>

       int euidaccess(const char *pathname, int mode);
       int eaccess(const char *pathname, int mode);

DESCRIPTION
       Like  access(2), euidaccess() checks permissions and existence of the file identified by its argument pathname.	However, whereas access(2)
       performs checks using the real user and group identifiers of the process, euidaccess() uses the effective identifiers.

       mode is a mask consisting of one or more of R_OK, W_OK, X_OK, and F_OK, with the same meanings as for access(2).

       eaccess() is a synonym for euidaccess(), provided for compatibility with some other systems.

RETURN VALUE
       On success (all requested permissions granted), zero is returned.  On error (at least one bit in  mode  asked  for  a  permission  that	is
       denied, or some other error occurred), -1 is returned, and errno is set appropriately.

ERRORS
       As for access(2).

VERSIONS
       The eaccess() function was added to glibc in version 2.4.

ATTRIBUTES
       For an explanation of the terms used in this section, see attributes(7).

       +------------------------+---------------+---------+
       |Interface		| Attribute	| Value   |
       +------------------------+---------------+---------+
       |euidaccess(), eaccess() | Thread safety | MT-Safe |
       +------------------------+---------------+---------+
CONFORMING TO
       These functions are nonstandard.  Some other systems have an eaccess() function.

NOTES
       Warning: Using this function to check a process's permissions on a file before performing some operation based on that information leads to
       race conditions: the file permissions may change between the two steps.	Generally, it is safer just to attempt the desired  operation  and
       handle any permission error that occurs.

       This function always dereferences symbolic links.  If you need to check the permissions on a symbolic link, use faccessat(2) with the flags
       AT_EACCESS and AT_SYMLINK_NOFOLLOW.

SEE ALSO
       access(2), chmod(2), chown(2), faccessat(2), open(2), setgid(2), setuid(2), stat(2), credentials(7), path_resolution(7)

COLOPHON
       This page is part of release 4.15 of the Linux man-pages project.  A description of the project, information about reporting bugs, and  the
       latest version of this page, can be found at https://www.kernel.org/doc/man-pages/.

								    2017-09-15							     EUIDACCESS(3)