## Name

`posix_spawn_file_actions` - configure file actions for `posix_spawn`

## Synopsis

```**c++
#include <spawn.h>

typedef struct posix_spawn_file_actions_t;

int posix_spawn_file_actions_init(posix_spawn_file_actions_t*);
int posix_spawn_file_actions_destroy(posix_spawn_file_actions_t*);

int posix_spawn_file_actions_addchdir(posix_spawn_file_actions_t*, const char*);
int posix_spawn_file_actions_addfchdir(posix_spawn_file_actions_t*, int);
int posix_spawn_file_actions_addclose(posix_spawn_file_actions_t*, int);
int posix_spawn_file_actions_adddup2(posix_spawn_file_actions_t*, int old_fd, int new_fd);
int posix_spawn_file_actions_addopen(posix_spawn_file_actions_t*, int fd, const char*, int flags, mode_t);
```

## Description

Configure a `posix_spawn_file_actions_t` object for use with [`posix_spawn`(2)](help://man/3/posix_spawn). This object can be used to let `posix_spawn()` set up file-related state for the spawned child process. The file actions are executed after creating the new process but before loading its binary in the order they were added to the `posix_spawn_file_actions_t` object.

A `posix_spawn_file_actions_t` object is allocated on the stack but starts in an undefined state.

`posix_spawn_file_actions_init()` initializes a `posix_spawn_file_actions_t` object that is in an undefined state and puts it in a valid state. It has to be called before the object can be passed to any other function.

`posix_spawn_file_actions_destroy()` frees up resources used by a valid `posix_spawn_file_actions_t` object and puts it into an undefined state. It has to be called after a `posix_spawn_file_actions_t` object is no longer needed.

It is valid to alternatingly call `posix_spawn_file_actions_init()` and `posix_spawn_file_actions_destroy()` on the same object,

`posix_spawn_file_actions_addchdir()` and `posix_spawn_file_actions_addfchdir()` make `posix_spawn()` change the current working directory before spawning a process, like `chdir` and `fchdir` would.. The current working directory affects the spawned child process, but also relative paths passed to later `posix_spawn_file_actions_add(f)chdir()` and `posix_spawn_file_actions_addopen()`, and relative paths passed to `posix_spawn()` for the executable path.

`posix_spawn_file_actions_addclose()` makes `posix_spawn()` close a file descriptor before spawning a process, like `close` would.

`posix_spawn_file_actions_addclose()` makes `posix_spawn()` dup a file descriptor before spawning a process, like `dup2` would.

`posix_spawn_file_actions_addopen()` makes `posix_spawn()` open a file with given flags and mode, like `open` would, and then makes it available under fd `fd` to the spawned process.

## Return value

In Minerva, these functions always succeed and return 0.

If the effect of a file action fails, the child will exit with exit code 127 before even executing the child binary.

## See also

-   [`posix_spawn`(2)](help://man/3/posix_spawn)