#1278 Memory leak with 'pngcairo crop'

[Christoph Bersch]

There is a memory leak when using set terminal pngcairo crop, a reported in the question How can I prevent gnuplot from eating my memory? on stackoverflow.

The minimal example to see this is:

set terminal pngcairo size 1000,1000 crop
do for [i=1:500] {
  set output 'plot.png'
  plot x w l
  set output
}

To check the memory consumption, run

> while true; do grep MemFree /proc/meminfo ; sleep 1s; done;

This gives me

MemFree:         5219028 kB
MemFree:         5047500 kB
MemFree:         4879064 kB
MemFree:         4702552 kB
MemFree:         4530532 kB
MemFree:         4358368 kB
MemFree:         4189808 kB
MemFree:         4013940 kB
MemFree:         3845568 kB
MemFree:         3673172 kB
MemFree:         3500916 kB
MemFree:         3331928 kB
MemFree:         3156720 kB
MemFree:         2984332 kB
MemFree:         2812300 kB
MemFree:         2636440 kB
MemFree:         2468060 kB
MemFree:         2299872 kB
MemFree:         2127880 kB
MemFree:         1959680 kB
MemFree:         1783764 kB
MemFree:         1615064 kB
MemFree:         1439212 kB
MemFree:         5222332 kB
MemFree:         5218296 kB

That happens at least since 4.6.0 and with current CVS. I have libcairo 1.12.2 and this is a 64bit build.

Christoph