Difference between revisions of "runtime error"
(→see also: add link to compile-time error) |
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== see also == | == see also == | ||
| + | * [[compile-time error]] | ||
* [https://www.freepascal.org/docs-html/user/userap4.html Appendix D in the Free Pascal User's Guide: “Run-time errors”] | * [https://www.freepascal.org/docs-html/user/userap4.html Appendix D in the Free Pascal User's Guide: “Run-time errors”] | ||
* [[RunError|procedure <syntaxhighlight lang="pascal" enclose="none">runError</syntaxhighlight>]] | * [[RunError|procedure <syntaxhighlight lang="pascal" enclose="none">runError</syntaxhighlight>]] | ||
* [https://www.freepascal.org/docs-html/current/user/userse58.html “Line numbers in run-time error backtraces”] in the Free Pascal User's Guide | * [https://www.freepascal.org/docs-html/current/user/userse58.html “Line numbers in run-time error backtraces”] in the Free Pascal User's Guide | ||
* {{Doc|package=RTL|unit=system|identifier=returnnilifgrowheapfails|text=<syntaxhighlight lang="pascal" enclose="none">system.returnNilIfGrowHeapFails</syntaxhighlight>}} | * {{Doc|package=RTL|unit=system|identifier=returnnilifgrowheapfails|text=<syntaxhighlight lang="pascal" enclose="none">system.returnNilIfGrowHeapFails</syntaxhighlight>}} | ||
Revision as of 01:52, 1 May 2020
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English (en) │
suomi (fi) │
A run-time error is an irreparable error condition that arises during the run-time, i.e. the execution of a program.
behavior
The FPC inserts code to detect a vast number of error situations. If such a situation is encountered, the standard run-time library will initiate the termination of the program. A run-time error number, and the address the error occurred at is being printed. This is the safest and cheapest error treatment.
comparative remarks
compile-time errors
In contrast to compile-time errors, which the compiler detects during compilation, run-time errors depend on the state of the program, thus can not be foreseen in advance. If a compile-time error is encountered, no executable program is generated.
exceptions
Run-time errors are the classical imperative approach in order to avoid inconsistent program states, which may eventually cause faulty program behavior.
If FPC's sysUtils unit is included, all run-time errors become exceptions (cf. system.runTimeErrors for details).
Unlike run-time errors those can be caught by try... except
on...do ... end blocks, provided a mode allowing exceptions – such as {$mode ObjFPC} or {$mode Delphi} – is being used.
A run-time error causes the program to terminate, while an exception may give the opportunity to “fix” the problem.
This standard behavior of system.runError can be altered by assigning a non-nil value to system.errorProc.
