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built-in variable | #error | ||||
Related Syntax | Related Concepts |
Purpose
One of the built-in program output streams, and the standard error output stream for OmniMark.
#error
always refers to a "standard error" ("stderr"), and can be used in the same manner as #process-output
.
If no "-log" command-line argument is given, OmniMark places all errors and informative messages in this stream. (Defining "-log" does not change the definition of #error
; it remains the "standard error" output.) If a system does not distinguish between "standard output" and "standard error", they are defined as the same destination.
Since this stream is considered "domain free" by default, neither the domain-free
modifier nor the "%z" modifier has any effect on it.
The following code illustrates the use of the #error
stream for standard error reporting:
local counter list-items do when number of list-items != list-count local counter temp put #error "Found a condition that shouldn't have happened:" set temp to number of list-items put #error " list-count = %d(list-count), but " _ "list-items has %d(temp) item(s).%n" halt with 2 ; signals an error condition while stopping done
Line-breaking and translation are never applied to the #error
stream.
On most systems, "standard error" is unbuffered. That is, text written to it is immediately output.
The #process-output
stream in OmniMark is normally buffered, which will lead to error messages appearing before output from #process-output
.
By default, the #error
stream in any program that uses referents is treated as if it were opened with referents-displayed
.
Related Syntax #process-output domain-free referents-displayed |
Related Concepts Input/Output Referents: suppressed Streams: changing modifiers on #process-output and #error |
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