upipe/uatomic.h header reference

Upipe thread-safe atomic operations More

• upipe/ubase.h
• upipe/config.h

• typedef [...] uatomic_uint32_t

• void uatomic_clean(uatomic_uint32_t *obj)
• bool uatomic_compare_exchange(uatomic_uint32_t *obj, uint32_t *expected, uint32_t desired)
• uint32_t uatomic_fetch_add(uatomic_uint32_t *obj, uint32_t operand)
• uint32_t uatomic_fetch_sub(uatomic_uint32_t *obj, uint32_t operand)
• void uatomic_init(uatomic_uint32_t *obj, uint32_t value)
• uint32_t uatomic_load(uatomic_uint32_t *obj)
• void uatomic_store(uatomic_uint32_t *obj, uint32_t value)

This API mimicks a partial C11 stdatomic implementation. Atomic variables must be initialized with uatomic_init before use, and released with uatomic_clean before deallocation.

This macro is declared in upipe/uatomic.h source file, line 34.

This function is declared in upipe/uatomic.h source file, line 139.

This function cleans up the uatomic variable.

Parameters list:

• obj: pointer to a uatomic variable

This function is declared in upipe/uatomic.h source file, line 102.

This function atomically replaces the uatomic variable, if it contains an expected value, with a desired value.

Parameters list:

• obj: pointer to a uatomic variable
• expected: reference to expected value, overwritten with actual value if it fails
• desired: desired value

The return value is false if the exchange failed

This function is declared in upipe/uatomic.h source file, line 118.

This function increments a uatomic variable.

Parameters list:

• obj: pointer to a uatomic variable
• operand: value to add

The return value is value before the operation

This function is declared in upipe/uatomic.h source file, line 130.

This function decrements a uatomic variable.

Parameters list:

• obj: pointer to a uatomic variable
• operand: value to substract

The return value is value before the operation

This function is declared in upipe/uatomic.h source file, line 63.

This function initializes a uatomic variable. It must be executed before any other uatomic call. It is not thread-safe.

Parameters list:

• obj: pointer to a uatomic variable
• value: initial value

This function is declared in upipe/uatomic.h source file, line 85.

This function returns the value of the uatomic variable.

Parameters list:

• obj: pointer to a uatomic variable

The return value is value

This function is declared in upipe/uatomic.h source file, line 74.

This function sets the value of the uatomic variable.

Parameters list:

• obj: pointer to a uatomic variable
• value: value to set

This typedef is declared in upipe/uatomic.h source file, line 54.

This typedef defines an atomic 32-bits unsigned integer. ARM platforms do not support larger atomic operations.

See also uring_lifo typedef and uring_fifo typedef.