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== `posix/bind_fd.hpp`
`bind_fd` is a utility class to bind a file descriptor to an explicit file descriptor for the child process.
[source,cpp]
----
struct bind_fd
{
// Inherit file descriptor with the same value.
/*
* This will pass descriptor 42 as 42 to the child process:
* @code
* process p{"test", {}, posix::bind_fd(42)};
* @endcode
*/
bind_fd(int target);
// Inherit an asio io-object as a given file descriptor to the child process.
/*
* This will pass the tcp::socket, as 42 to the child process:
* @code
* extern tcp::socket sock;
* process p{"test", {}, posix::bind_fd(42, sock)};
* @endcode
*/
template<typename Stream>
bind_fd(int target, Stream && str);
// Inherit a `FILE` as a given file descriptor to the child process.
/* This will pass the given `FILE*`, as 42 to the child process:
process p{"test", {}, posix::bind_fd(42, stderr)};
*/
bind_fd(int target, FILE * f);
// Inherit a file descriptor with as a different value.
/* This will pass 24 as 42 to the child process:
process p{"test", {}, posix::bind_fd(42, 24)};
*/
bind_fd(int target, int fd):
// Inherit a null device as a set descriptor.
/* This will a null device as 42 to the child process:
process p{"test", {}, posix::bind_fd(42, nullptr)};
*/
bind_fd(int target, std::nullptr_t);
// Inherit a newly opened-file as a set descriptor.
/* This will pass a descriptor to "extra-output.txt" as 42 to the child process:
process p{"test", {}, posix::bind_fd(42, "extra-output.txt")};
*/
bind_fd(int target, const filesystem::path & pth, int flags = O_RDWR | O_CREAT);
};
----
Using `bind_fd` can be used to inherit file descriptors explicitly, because no unused one will be.
[source,cpp]
----
----
|
