notcurses_fds(3)

nick black

v1.6.1

NAME

notcurses_fds - dumping file descriptors and subprocesses to planes

SYNOPSIS

#include <notcurses/notcurses.h>

struct ncplane;
struct ncfdplane;
struct ncsubproc;

typedef struct ncfdplane_options {
  void* curry; // parameter provided to callbacks
  bool follow; // keep reading after hitting end?
} ncfdplane_options;

typedef struct ncsubproc_options {
  void* curry; // parameter provided to callbacks
  uint64_t restart_period;  // restart after exit
} ncsubproc_options;

typedef int(ncfdplane_callback)(struct ncfdplane n, const void* buf, size_t s, void* curry);

typedef int(ncfdplane_done_cb)(struct ncfdplane n, int fderrno, void* curry);

struct ncfdplane* ncfdplane_create(struct ncplane* n, const ncfdplane_options* opts, int fd, ncfdplane_callback cbfxn, ncfdplane_done_cb donecbfxn);

struct ncplane* ncfdplane_plane(struct ncfdplane* n);

int ncfdplane_destroy(struct ncfdplane* n);

struct ncsubproc* ncsubproc_createv(struct ncplane* n, const ncsubproc_options* opts, const char* bin, char* const arg[], ncfdplane_callback cbfxn, ncfdplane_done_cb donecbfxn);

struct ncsubproc* ncsubproc_createvp(struct ncplane* n, const ncsubproc_options* opts, const char* bin, char* const arg[], ncfdplane_callback cbfxn, ncfdplane_done_cb donecbfxn);

struct ncsubproc* ncsubproc_createvpe(struct ncplane* n, const ncsubproc_options* opts, const char* bin, char* const arg[], char* const env[], ncfdplane_callback cbfxn, ncfdplane_done_cb donecbfxn);

struct ncplane* ncsubproc_plane(struct ncsubproc* n);

int ncsubproc_destroy(struct ncsubproc* n);

DESCRIPTION

These widgets cause a file descriptor to be read until EOF, and written to a scrolling ncplane. The reading will take place in a notcurses-managed context (the particulars of this context are not defined, and should not be depended upon), which will invoke the provided callbacks with the data read. Essentially, they are simply portable interfaces to asynchronous reading, with ncsubproc also providing subprocess management.

If ncsubproc_destroy is called before the subprocess has exited, it will be sent a SIGKILL. If ncsubproc_destroy or ncfdplane_destroy is called while a callback is being invoked, the destroy function will block until the callback is done being invoked. If a user callback returns non-0, the calling object will destroy itself. If a user callback calls the relevant destroy function itself, the thread will exit as if non-0 had been returned, and the ncsubproc’s resources will at that time be reclaimed.

It is essential that the destroy function be called once and only once, whether it is from within the thread’s context, or external to that context.

NOTES

ncsubproc makes use of pidfds and pidfd_send_signal(2), and thus makes reliable use of signals (it will never target a process other than the true subprocess).

RETURN VALUES

SEE ALSO

pidfd_open(2), notcurses(3), notcurses_plane(3)