Quiet

Status: Stable

documented, exercised by the test suite and/or worked examples, with no known limitations recorded.

Description

Quiet[expr]

evaluates expr with messages suppressed and returns its value. Quiet[expr, spec] suppresses all messages regardless of spec.

Examples (4)

Every input below was run against the current Mathilda build and its output recorded.

Basic examples (2)

In[1]:= Quiet[1/0]
Out[1]= ComplexInfinity

In[2]:= Quiet[Log[0]]
Out[2]= -Infinity

Applications (2)

The Power::infy message is silenced; the value is unchanged

In[3]:= Quiet[1/0]
Out[3]= ComplexInfinity

The value comes back with no printed warning

In[4]:= Quiet[Log[0]]
Out[4]= -Infinity

Implementation notes

Algorithm. Quiet is HoldAll, Protected, so the argument is evaluated under the suppression rather than before it. builtin_quiet brackets the evaluation between mth_msg_suppress_push() and mth_msg_suppress_pop() and returns the value (an in-flight Throw sentinel propagates unchanged). The optional spec of the two-argument form — a message name or list — is accepted and ignored: all messages are suppressed, a harmless superset of any requested set.

Data structures. A single static nesting depth g_msg_suppress_depth (> 0 ⇒ suppress). The depth is a count, so Quiet nests correctly. Inside the funnel mth_message_v still calls mth_msg_note_fired() before testing mth_msg_suppressed(), so a message under Quiet still fires (an enclosing Check sees it) and only its printing is silenced. A paired mth_msg_suppress_depth_save/_load lets TimeConstrained's siglongjmp restore the depth if a timeout unwinds out of a Quiet region, which would otherwise leave messages silenced for the rest of the session.

Complexity / limits. O(1) push/pop around the inner evaluation. Quiet affects only the display of diagnostics; it changes neither the value computed nor whether a message is considered to have fired.

• HoldAll, so the argument is evaluated under the suppression, not before it.
• A message still fires while suppressed (an enclosing Check sees it); only the printing is silenced.

Attributes: HoldAll, Protected.

References

See also: HoldAll, Check

• Source: src/message.c
• Specification: docs/spec/builtins/control-flow.md
• Tests: tests/test_dirichletcharacter.c
• Tests: tests/test_factorinteger.c
• Tests: tests/test_files.c
• Tests: tests/test_graph.c

Notes & additional examples

Notes

Quiet[expr] evaluates expr and returns its value with any messages suppressed. It is HoldAll, so the suppression is in force during the evaluation. The optional second argument (a message name or list) is accepted and ignored — all messages are suppressed, which is a harmless superset of any requested set.

Suppression silences only the printing. A message still fires while quieted, so an enclosing Check still sees it — which is exactly what the common Quiet[Check[expr, failexpr]] pattern relies on.