Module diag 

Diagnostics as lib/cgraph/agerror.c reports them: agerrorf prints Error: ... and raises the error level that dot’s main returns as its exit status (graphviz_errors + agerrors()), while the layout and the output go on. agwarningf prints Warning: ... and does not change the status.

The level is per thread, so concurrent in-process renders do not see each other’s errors.

Functions

agerr_prev

agerr(AGPREV, msg): continues the previous message.

agerrorf

agerrorf(msg): msg is the C format output, normally ending in a newline.

agwarningf

agwarningf(msg).

emit_once

emit_once(str): true the first time key is seen on this thread.

error_count

Number of errors reported on this thread since the last reset_errors.

fmt_g

C printf("%.{prec}g", v) on the reference platform (macOS libc), as diagnostics and renderers print numbers.

quietly

Runs f as a repeat of work C does once. The port sizes labels and nodes again after C’s common_init_node/common_init_edge/do_graph_label (for ports, splines and rendering), and the diagnostics of those calls (HTML label warnings and errors, bad label format, size too small for label) must not print a second time.

reporting

False inside quietly and silently: label and node sizing diagnostics are reported only outside them.

reporting_ports

False inside silently: port warnings are reported only outside it.

reset_errors

Clears the error count and the once-only messages of this thread.

silently

quietly, and port warnings too, for a repeat that C does not make at all.