PTHREAD_CANCEL(3) | Library Functions Manual | PTHREAD_CANCEL(3)

# NAME

`pthread_cancel` — cancel execution of a thread

# SYNOPSIS

POSIX Threads Library (libpthread, -lpthread)
`#include <pthread.h>`

int
`pthread_cancel`(pthread_t thread);

# DESCRIPTION

The `pthread_cancel`() function requests that thread be cancelled. The target thread's cancelability state and type determines when the cancellation takes effect. When the cancellation is acted on, the cancellation cleanup handlers for thread are called. When the last cancellation cleanup handler returns, the thread-specific data destructor functions will be called for thread. When the last destructor function returns, thread will be terminated.

The cancellation processing in the target thread runs asynchronously with respect to the calling thread returning from `pthread_cancel`().

A status of `PTHREAD_CANCELED` is made available to any threads joining with the target. The symbolic constant `PTHREAD_CANCELED` expands to a constant expression of type (void *) whose value matches no pointer to an object in memory nor the value `NULL`.

# RETURN VALUES

If successful, the `pthread_cancel`() functions will return zero. Otherwise an error number will be returned to indicate the error.

# ERRORS

`pthread_cancel`() will fail if:

[`ESRCH`]
  No thread could be found corresponding to that specified by the given thread ID.

# SEE ALSO

pthread_cleanup_pop(3), pthread_cleanup_push(3), pthread_exit(3), pthread_join(3), pthread_setcancelstate(3), pthread_setcanceltype(3), pthread_testcancel(3)

# STANDARDS

`pthread_cancel`() conforms to ISO/IEC 9945-1:1996 (“POSIX.1”).

June 13, 2025 | Debian