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notcurses_stats(3) notcurses_stats(3)

NAME

notcurses_stats - notcurses runtime statistics

SYNOPSIS

#include <notcurses/notcurses.h>

typedef struct ncstats {
  // purely increasing stats
  uint64_t renders;          // number of successful renders
  uint64_t failed_renders;   // aborted renders, should be 0
  uint64_t render_bytes;     // bytes emitted to ttyfp
  int64_t render_max_bytes;  // max bytes emitted for a frame
  int64_t render_min_bytes;  // min bytes emitted for a frame
  uint64_t render_ns;        // nanoseconds spent in render+raster
  int64_t render_max_ns;     // max ns spent in render+raster for a frame
  int64_t render_min_ns;     // min ns spent in render+raster for a frame
  uint64_t writeout_ns;      // nanoseconds spent writing frames to terminal
  int64_t writeout_max_ns;   // max ns spent writing out a frame
  int64_t writeout_min_ns;   // min ns spent writing out a frame
  uint64_t cellelisions;     // cells elided entirely
  uint64_t cellemissions;    // cells emitted
  uint64_t fgelisions;       // RGB fg elision count
  uint64_t fgemissions;      // RGB fg emissions
  uint64_t bgelisions;       // RGB bg elision count
  uint64_t bgemissions;      // RGB bg emissions
  uint64_t defaultelisions;  // default color was emitted
  uint64_t defaultemissions; // default color was elided
  // current state -- these can decrease
  uint64_t fbbytes;          // bytes devoted to framebuffers
  unsigned planes;           // planes currently in existence
} ncstats;

    

ncstats* notcurses_stats_alloc(struct notcurses* nc);

void notcurses_stats(struct notcurses* nc, ncstats* stats);

void notcurses_stats_reset(struct notcurses* nc, ncstats* stats);

DESCRIPTION

notcurses_stats_alloc allocates an ncstats object. This should be used rather than allocating the object in client code, to future-proof against the struct being enlarged by later Notcurses versions.

notcurses_stats acquires an atomic snapshot of statistics, primarily related to notcurses_render(3). notcurses_stats_reset does the same, but also resets all cumulative stats (immediate stats such as fbbytes are not reset).

renders is the number of successful calls to notcurses_render(3) or notcurses_render_to_buffer(3). failed_renders is the number of unsuccessful calls to these functions. failed_renders should be 0; renders are not expected to fail except under exceptional circumstances. should notcurses_render(3) fail while writing out a frame to the terminal, it counts as a failed render.

render_max_bytes and render_min_bytes track the maximum and minimum number of bytes used rasterizing a frame. A given state of Notcurses does not correspond to a unique number of bytes; the size is also dependent on the existing terminal state. As a first approximation, the time a terminal takes to ingest and reflect a frame is dependent on the size of the rasterized frame.

render_ns, render_max_ns, and render_min_ns track the total amount of time spent rendering and rasterizing frames in nanoseconds. Rendering and rasterizing takes place in notcurses_render(3), and is the entirety of notcurses_render_to_buffer(3). These steps are independent of the terminal.

writeout_ns, writeout_max_ns, and writeout_min_ns track the total amount of time spent writing frames to the terminal. This takes place in only notcurses_render(3). If notcurses_render_to_buffer(3) is used, the user is responsible for writing out the frame, and it will not be tracked by any stat.

cellemissions reflects the number of EGCs written to the terminal. cellelisions reflects the number of cells which were not written, due to damage detection.

fbbytes is the total number of bytes devoted to framebuffers throughout the struct notcurses context. planes is the number of planes in the context. Neither of these stats can reach 0, due to the mandatory standard plane.

NOTES

Unsuccessful render operations do not contribute to the render timing stats.

RETURN VALUES

Neither notcurses_stats nor notcurses_stats_reset can fail. Neither returns any value. notcurses_stats_alloc returns a valid ncstats object on success, or NULL on failure.

SEE ALSO

notcurses(3), notcurses_render(3)

AUTHORS

nick black <nickblack@linux.com>.
v2.0.4