mq_open.2 (2010 09)

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mq_open(2) mq_open(2)

b. Contain no path name component consisting of a dot or dot-dot. For example,

/./tmp and

/../tmp are invalid.

c. Contain no illegal characters.

d. Contain no path name components longer that

_POSIX_NAME_MAX

e. Entire name should not be longer that

_POSIX_PATH_MAX

To use this function, link in the realtime library by specifying

-lrt on the compiler or linker command

line.

Security Restrictions

Some or all of the actions associated with this system call are subject to compartmental restrictions. See

compartments (5) for more information about compartmentalization on systems that support that feature.

Compartmental restrictions can be overridden if the process possesses the

COMMALLOWED privilege

(

PRIV_COMMALLOWED

). Processes owned by the superuser may not have this privilege. Processes

owned by any user may have this privilege, depending on system conﬁguration.

Some or all of the actions associated with this system call require the

DACWRITE privilege

(

PRIV_DACWRITE

). Processes owned by the superuser have this privilege. Processes owned by other

users may have this privilege, depending on system conﬁguration.

See privileges (5) for more information about privileged access on systems that support ﬁne-grained

privileges.

RETURN VALUE

mq_open() returns the following values:

n Successful completion. n is a message queue descriptor for the opened message queue and is

greater than or equal to

-1 Failure. errno is set to indicate the error.

ERRORS

mq_open() fails, errno is set to one of the following values:

[EACCES] The message queue exists and the permissions speciﬁed by oﬂag are denied, or the

message queue does not exist and permission to create the queue is denied.

[EEXIST] The

O_CREAT and O_EXCL ﬂags are set in oﬂag and the named message queue

exists.

[EINTR]

mq_open() was interrupted by a signal.

[EINVAL] The argument name, does not conform to the Message Queue Naming Convention .

O_CREAT has been speciﬁed in oﬂag, the value of attr is not NULL, and either

mq_maxmsg or mq_msgsize is less than or equal to zero.

[EMFILE] Too many message queue descriptors are currently in use by this process.

[ENAMETOOLONG]

The length of the name string exceeds

PATH_MAX bytes, or the length of a (path

name) component of the name string exceeds NAME_MAX bytes while

_POSIX_NO_TRUNC is in effect.

[ENFILE] Too many message queues are currently open in the system.

[ENOENT] The

O_CREAT ﬂag is not set in oﬂag and the named message queue does not exist.

[ENOSPC] There are insufﬁcient resources for the creation of the new message queue.

[ENOSYS]

mq_open() is not supported by the implementation.