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QNX SDP is a cross-compiling and debugging environment, including an IDE and command-line tools, for building binary images and programs for target boards running the QNX OS 8.0.
Utilities & Libraries
C Library Reference
I
iofunc_readlink()
Verify the attributes being used to read a link

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      - ilogb(), ilogbf(), ilogbl()
        Compute the integral part of a logarithm
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        Variables for IPv6 addresses
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        Read an 8-bit value from a port
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        Read a 32-bit value from a port
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        Read 32-bit values from a port
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        Initialize the supplementary group access list
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        Initialize a pseudo-random number generator
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        Add or update a watch for filesystem events associated with a path
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        Structure that describes a watched filesystem event
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        Initialize the inode notify system
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        Detach an interrupt thread by ID
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        Structure of a connect message that redirects a client to another resource
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        Retrieve server attributes
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        Verify that the client has a given resource manager ability
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        Handle an _IO_ACL message
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        Default handler for the acl callout
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        Initialize the per-name attribute structure associated with a device
      - iofunc_attr_lock()
        Lock the attribute structure
      - iofunc_attr_t
        I/O attribute structure
      - iofunc_attr_trylock()
        Try to lock the attribute structure
      - iofunc_attr_unlock()
        Unlock the attribute structure
      - iofunc_check_access()
        Check access permissions
      - iofunc_check_msg_default()
        Check a message
      - iofunc_chmod()
        Handle an _IO_CHMOD message
      - iofunc_chmod_default()
        Default handler for _IO_CHMOD messages
      - iofunc_chown()
        Handle an _IO_CHOWN message
      - iofunc_chown_default()
        Default handler for _IO_CHOWN messages
      - iofunc_client_info_able()
        Return information about a client connection, including abilities
      - iofunc_client_info_ext()
        Return information about a client connection
      - iofunc_client_info_ext_free()
        Free the structure used for information about a client connection
      - iofunc_close_dup()
        Free all locks allocated for the client process
      - iofunc_close_dup_default()
        Default handler for _IO_CLOSE messages
      - iofunc_close_ocb()
        Return the memory allocated for an OCB
      - iofunc_close_ocb_default()
        Return the memory allocated for an OCB
      - iofunc_devctl()
        Handle an _IO_DEVCTL message
      - iofunc_devctl_default()
        Default handler for _IO_DEVCTL messages
      - iofunc_devctl_verify()
        Perform validation that's common to all handlers for _IO_DEVCTL messages
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        Handle an _IO_FDINFO message
      - iofunc_fdinfo_default()
        Default handler for _IO_FDINFO messages
      - iofunc_func_init()
        Initialize the default POSIX-layer function tables
      - iofunc_link()
        Link two directory entries
      - iofunc_lock()
        Lock a resource
      - iofunc_lock_default()
        Default handler for _IO_LOCK messages
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        Default handler for the lock_ocb callout
      - iofunc_lseek()
        Handle an _IO_LSEEK message
      - iofunc_lseek_default()
        Default handler for _IO_LSEEK messages
      - iofunc_mknod()
        Verify a client's ability to make a new filesystem entry point
      - iofunc_mmap()
        Handle an _IO_MMAP message
      - iofunc_mmap_default(), iofunc_mmap_default_ext()
        Default handler for _IO_MMAP messages
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        Handle an _IO_MMAP message
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        Clean up the IOFUNC_MOUNT_T structure
      - iofunc_mount_init()
        Initialize the IOFUNC_MOUNT_T structure
      - iofunc_mount_set_time()
        Set the timestamp resolution for iofunc functions and structures
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        I/O mount structure
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        Add, poll, or remove a notification handler
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        Remove notification entries from a list
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        Send notifications to queued clients
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        Initialize an Open Control Block (OCB)
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        Allocate an iofunc Open Control Block
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        Release Open Control Block resources
      - iofunc_ocb_free()
        Deallocate an iofunc Open Control Block's memory
      - iofunc_ocb_t
        Open Control Block structure
      - iofunc_open()
        Verify a client's ability to open or to create a resource
      - iofunc_open_default(), iofunc_open_default_cinfo()
        Default handler for _IO_CONNECT messages
      - iofunc_openfd()
        Increment count and locking flags
      - iofunc_openfd_default()
        Default handler for _IO_OPENFD messages
      - iofunc_pathconf()
        Support pathconf() requests
      - iofunc_pathconf_default()
        Default handler for _IO_PATHCONF messages
      - iofunc_read_default()
        Default handler for _IO_READ messages
      - iofunc_read_verify()
        Verify a client's read access to a resource
      - iofunc_readlink()
        Verify the attributes being used to read a link
      - iofunc_rename()
        Do permission checks for a _IO_CONNECT_RENAME message
      - iofunc_space_verify()
        Do permission checks for the _IO_SPACE message
      - iofunc_stat(), iofunc_stat_format()
        Populate a stat structure
      - iofunc_stat_default()
        Default handler for _IO_STAT messages
      - iofunc_sync()
        Indicate if synchronization is needed
      - iofunc_sync_default()
        Default handler for _IO_SYNC messages
      - iofunc_sync_verify()
        Verify permissions to sync
      - iofunc_time_update()
        Update time stamps
      - iofunc_unblock()
        Unblock OCBs
      - iofunc_unblock_default()
        Default unblock handler
      - iofunc_unlink()
        Verify that an entry can be unlinked
      - iofunc_unlock_ocb_default()
        Default handler for the unlock_ocb callout
      - iofunc_utime()
        Update time stamps
      - iofunc_utime_default()
        Default handler for _IO_UTIME messages
      - iofunc_write_default()
        Default handler for _IO_WRITE messages
      - iofunc_write_verify()
        Verify a client's write access to a resource
      - ionotify()
        Arm a resource manager
      - isalnum()
        Test a character to see if it's alphanumeric
      - isalpha()
        Test a character to see if it's alphabetic
      - isascii()
        Test a character to see if it's a 7-bit ASCII character
      - isatty()
        Test to see if a file descriptor is associated with a terminal
      - isblank()
        Test a character to see if it's a blank character
      - iscntrl()
        Test a character to see if it's a control character
      - isdigit()
        Test a character to see if it's a decimal digit
      - isfdtype()
        Test the file type of a file descriptor
      - isfinite()
        Determine if a number is finite
      - isgraph()
        Test a character to see if it's any printable character except a space
      - isgreater()
        Determine whether one floating-point number is greater than another
      - isgreaterequal()
        Determine whether one floating-point number is greater than or equal to another
      - isinf()
        Test for infinity
      - isless()
        Determine whether one floating-point number is less than another
      - islessequal()
        Determine whether one floating-point number is less than or equal to another
      - islessgreater()
        Determine whether one floating-point number is less than or greater than another
      - islower()
        Test a character to see if it's a lowercase letter
      - isnan()
        Test for not-a-number (NaN)
      - isnormal()
        Determine whether a floating-point number is normal
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        Test a character to see if it's any printable character, including a space
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        Test a character to see if it's any punctuation character
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        Test a character to see if it's a whitespace character
      - isunordered()
        Determine whether two floating-point numbers are unordered
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        Test a character to see if it's an uppercase letter
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        Test a wide character to see if it's alphanumeric
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        Test a wide character to see if it's alphabetic
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        Test a wide character to see if it's a blank character
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        Test a wide character to see if it's a control character
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        Test a wide character to see if it's a given character class
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        Test a wide character to see if it's a decimal digit
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        Test a wide character to see if it's any printable character except space
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        Test a wide character to see if it's a lowercase letter
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        Test a wide character to see if it's any printable character, including space
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        Test a wide character to see if it's any punctuation character
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        Test a wide character to see if it's a whitespace character
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        Test a character to see if it's an uppercase letter
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        Test a wide character to see if it's a hexadecimal digit
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        Test a character to see if it's a hexadecimal digit
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iofunc_readlink()

QNX SDP8.0C Library ReferenceAPIDeveloper

Verify the attributes being used to read a link

Synopsis:

#include <sys/iofunc.h>

int iofunc_readlink( resmgr_context_t *ctp,
                     io_readlink_t *msg,
                     iofunc_attr_t *attr,
                     struct _client_info *info );

Arguments:

ctp: A pointer to a resmgr_context_t structure that the resource-manager library uses to pass context information between functions.
msg: A pointer to the io_readlink_t structure that contains the message that the resource manager received.
attr: A pointer to the iofunc_attr_t structure that describes the characteristics of the device that's associated with your resource manager.
info: A pointer to a _client_info structure that contains the information about a client connection. For information about this structure, see ConnectClientInfo().

Library:

libc

Use the -l c option to qcc to link against this library. This library is usually included automatically.

Description:

The iofunc_readlink() helper function supports readlink() requests by verifying that attr isn't NULL, and that it refers to a symbolic link.

Returns:

EBADFSYS: The attr argument is NULL.
EINVAL: The iofunc_attr_t structure doesn't refer to a symbolic link.
EOK: Successful completion.

Classification:


Safety:
Cancellation point	No
Signal handler	Yes
Thread	Yes

Page updated: August 11, 2025