A

The functions, macros, and data structures in the C library are described here in alphabetical order.

A ¦ B ¦ C ¦ D ¦ E ¦ F ¦ G ¦ H ¦ I ¦ J ¦ K ¦ L ¦ M ¦ N ¦ O ¦ P ¦ Q ¦ R ¦ S ¦ T ¦ U ¦ V ¦ W ¦ X ¦ Y ¦ Z

The following are described elsewhere:

For information about:	See:
APS_INIT_DATA()	SchedCtl()

This chapter describes the API components whose names begin with “A”.

abort()
Raise the SIGABRT signal to terminate program execution
abs()
Return the absolute value of an integer
accept()
Accept a connection on a socket
access()
Check to see if a file or directory can be accessed
acl_add_perm()
Add a permission to an access control list (ACL) permissions set
acl_calc_mask()
Calculate the group class mask for an access control list (ACL)
acl_clear_perms()
Clear all permissions from an ACL permissions set
acl_copy_entry()
Copy the contents of one ACL entry into another
acl_copy_ext()
Copy an ACL from system space to user space
acl_copy_int()
Copy an ACL from user space to system space
acl_create_entry()
Create an entry in an access control list
acl_delete_entry()
Delete an entry from an access control list (ACL)
acl_delete_perm()
Delete a permission from an ACL permissions set
acl_dup()
Duplicate an access control list (ACL) in a working storage area
acl_free()
Free the working storage area allocated for an access control list (ACL) data object
acl_from_text()
Create an access control list (ACL) from text
acl_get_entry()
Get an entry in an access control list (ACL)
acl_get_fd()
Get the access control list associated with a file descriptor
acl_get_file()
Get the ACL for a given path
acl_get_perm_np()
Test whether a given permission is present in an ACL permissions set
acl_get_permset()
Get a permissions set from an ACL entry
acl_get_qualifier()
Get the qualifier from an ACL entry
acl_get_tag_type()
Get the type of tag from an ACL entry
acl_init()
Allocate and initialize an access control list (ACL) working storage area
acl_set_fd()
Set the access ACL for the object associated with a file descriptor
acl_set_file()
Set the access control list for a path
acl_set_permset()
Set the permissions set in an ACL entry
acl_set_qualifier()
Set the qualifier for an ACL entry
acl_set_tag_type()
Set the tag type of an ACL entry
acl_size()
Determine the size of the external form of an ACL
acl_to_text()
Convert an access control list (ACL) into text
acl_valid()
Validate an access control list (ACL)
acos(), acosf(), acosl()
Compute the arccosine of an angle
acosh(), acoshf(), acoshl()
Compute the inverse hyperbolic cosine
addrinfo
TCP/IP address information
aio_cancel()
Cancel an asynchronous I/O operation
aio_error()
Get the error status for an asynchronous I/O operation
aio_fsync()
Asynchronously synchronize a file
aio_read(), aio_read64()
Asynchronously read from a file
aio_return()
Get the return status for an asynchronous I/O operation
aio_suspend()
Wait for asynchronous I/O operations to be completed
aio_write(), aio_write64()
Asynchronously write to a file
aiocb, aiocb64
Asynchronous I/O control block
alarm()
Schedule an alarm
alignas, __alignas_is_defined
Specify the alignment of an object
aligned_alloc()
Allocate aligned memory
alignof(), __alignof_is_defined
Get the alignment of a type
alloca()
Allocate automatic space from the stack
alphasort()
Compare two directory entries
_amblksiz
The arena size for heap allocations
_argc
The number of arguments passed to main()
_argv
A pointer to the vector of arguments passed to main()
asctime(), asctime_r()
Convert time information to a string
asin(), asinf(), asinl()
Compute the arcsine of an angle
asinh(), asinhf(), asinhl()
Compute the inverse hyperbolic sine
assert()
Display a diagnostic message and optionally terminate the program
at_quick_exit()
Register functions to be called during program termination via quick_exit()
atan(), atanf(), atanl()
Compute the arctangent of an angle
atan2(), atan2f(), atan2l()
Compute the arctangent, determining the quadrant
atanh(), atanhf(), atanhl()
Compute an inverse hyperbolic tangent
atexit()
Register functions to be called during normal program termination
atof()
Convert a string into a double
atoi()
Convert a string into an integer
atol(), atoll()
Convert a string into a long integer
ATOMIC_*_LOCK_FREE
Macros that indicate whether an atomic type is lock-free (C11)
atomic_*
Data types for atomic operations (C11)
atomic_add()
Safely add to a variable (QNX Neutrino)
atomic_add_value()
Safely add to a variable, returning the previous value (QNX Neutrino)
atomic_clr()
Safely clear bits in a variable (QNX Neutrino)
atomic_clr_value()
Safely clear bits in a variable, returning the previous value (QNX Neutrino)
atomic_compare_exchange_strong(), atomic_compare_exchange_strong_explicit(), atomic_compare_exchange_weak(), atomic_compare_exchange_weak_explicit(),
Compare and potentially exchange the value of an atomic object (C11)
atomic_exchange(), atomic_exchange_explicit()
Atomically change the value of an atomic object (C11)
atomic_fetch_add(), atomic_fetch_add_explicit()
Atomically add to the value of an atomic object (C11)
atomic_fetch_and(), atomic_fetch_and_explicit()
Atomically AND a value into an atomic object (C11)
atomic_fetch_or(), atomic_fetch_or_explicit()
Atomically OR a value into an atomic object (C11)
atomic_fetch_sub(), atomic_fetch_sub_explicit()
Atomically subtract the value of an atomic object (C11)
atomic_fetch_xor(), atomic_fetch_xor_explicit()
Atomically XOR a value into an atomic object (C11)
atomic_flag_clear(), atomic_flag_clear_explicit()
Atomically clear a flag (C11)
atomic_flag_test_and_set(), atomic_flag_test_and_set_explicit()
Atomically set a flag (C11)
atomic_init()
Initialize an atomic object (C11)
atomic_is_lock_free()
Determine whether atomic operations on an object are lock-free (C11)
atomic_load(), atomic_load_explicit()
Atomically read the value of an atomic object (C11)
atomic_set()
Safely set bits in a variable (QNX Neutrino)
atomic_set_value()
Safely set bits in a variable, returning the previous value (QNX Neutrino)
atomic_signal_fence()
Fence between a thread and a signal handler executed in the same thread (C11)
atomic_store(), atomic_store_explicit()
Atomically set the value of an atomic object (C11)
atomic_sub()
Safely subtract from a variable (QNX Neutrino)
atomic_sub_value()
Safely subtract from a variable, returning the previous value (QNX Neutrino)
atomic_thread_fence()
Generic memory order-dependent fence synchronization primitive (C11)
atomic_toggle()
Safely toggle bits in a variable (QNX Neutrino)
atomic_toggle_value()
Safely toggle bits in a variable, returning the previous value (QNX Neutrino)
_auxv
A pointer to a vector of auxiliary arguments to main()