libdill: Structured Concurrency for C

NAME

bundle_mem - create an empty coroutine bundle

SYNOPSIS

#include <libdill.h>

int bundle_mem(
    struct bundle_storage* mem);

DESCRIPTION

Coroutines are always running in bundles. Even a single coroutine created by go gets its own bundle. A bundle is a lifetime control mechanism. When it is closed, all coroutines within the bundle are canceled.

This function creates an empty bundle. Coroutines can be added to the bundle using the bundle_go and bundle_go_mem functions.

To wait until coroutines in the bundle finish use bundle_wait function.

When hclose() is called on the bundle, all the coroutines contained in the bundle will be canceled. In other words, all the blocking functions within the coroutine will start failing with an ECANCELED error. The hclose() function itself won't exit until all the coroutines in the bundle exit.

This function allows to avoid one dynamic memory allocation by storing the object in user-supplied memory. Unless you are hyper-optimizing use bundle instead.

mem: The structure to store the newly created object in. It must not be deallocated before the object is closed.

RETURN VALUE

In case of success the function returns handle of the newly create coroutine bundle. In case of error it returns -1 and sets errno to one of the values below.

ERRORS

EMFILE: The maximum number of file descriptors in the process are already open.
ENFILE: The maximum number of file descriptors in the system are already open.
ENOMEM: Not enough memory.

EXAMPLE

int b = bundle();
bundle_go(b, worker());
bundle_go(b, worker());
bundle_go(b, worker());
/* Give wrokers 1 second to finish. */
bundle_wait(b, now() + 1000);
/* Cancel any remaining workers. */
hclose(b);