Something

(gdb) printf "%p\n", this->cairo
0x851b6f0
(gdb) s
107       if (this->cairo != NULL) {
(gdb) s
108         cairo_status_t status = cairo_status (this->cairo);
(gdb) printf "%d\n",status
0
(gdb) s
*INT_cairo_status (cr=0x851b6f0) at cairo.c:3428
3428    {
Current language:  auto; currently c
(gdb) s
3430    }
(gdb) s
CairoOutputDev::setCairo (this=0x853a2f0, cairo=0x0) at CairoOutputDev.cc:109
109         if (status) {
Current language:  auto; currently c++
(gdb) printf "%d\n",status
0
(gdb) s
110           warning("cairo context error: %s\n", cairo_status_to_string(status));
(gdb) s
cairo_status_to_string (status=CAIRO_STATUS_NULL_POINTER) at cairo.c:3443
3443    {
Current language:  auto; currently c
(gdb) printf "%d\n",status
7