.TH IM_HISTORY 3 "22 April 1991"
.SH NAME
im_histlin, im_updatehist, im_history_get \- manage image history
.SH SYNOPSIS
.B #include <vips/vips.h>

int im_histlin( IMAGE *im, const char *fmt, ... );
.br
int im_updatehist( IMAGE *out, const char *name, int argc, char *argv[] );
.br
const char *im_history_get( IMAGE *im );

.br
.SH DESCRIPTION
.B im_histlin(3)
formats its arguments as printf(3), appends " # time-and-date", and appends
the whole line of text to the image history. The string is typically the
command-line action that would be required to do whatever it is that you've
just done to the image.

.B im_updatehist(3)
is given a standard argc/argv, formats them appropriately, and calls
im_histlin(3) for you. Note that the program name is passed separately.

.B im_history_get(3)
returns the entire history of an image as a single C string, one action per
line. No need to free, but you mustn't modify either.

.SH RETURN VALUE
The function returns 0 on success and -1 on error.
.SH SEE ALSO
im_cp_desc(3).
.SH COPYRIGHT
Imperial College, London, 2007.