Chapter 14
Run time errors

1 Invalid function number

An invalid operating system call was attempted.

2 File not found

Reported when trying to erase, rename or open a non-existent le.

3 Path not found

Reported by the directory handling routines when a path does not exist or is invalid. Also reported when trying to access a non-existent le.

4 Too many open les

The maximum number of currently opened les by your process has been reached. Certain operating systems limit the number of les which can be opened concurrently, and this error can occur when this limit has been reached.

5 File access denied

Permission accessing the le is denied. This error might be caused by several reasons:

• Trying to open for writing a le which is read only, or which is actually a directory.
• File is currently locked or used by another process.
• Trying to create a new le, or directory while a le or directory of the same name already exists.
• Trying to read from a le which was opened in write only mode.
• Trying to write from a le which was opened in read only mode.
• Trying to remove a directory or le while it is not possible.
• No permission to access the le or directory.

6 Invalid le handle

If this happens, the le variable you are using is trashed; it indicates that your memory is corrupted.

12 Invalid le access code

Reported when a reset or rewrite is called with an invalid FileMode value.

15 Invalid drive number

The number given to the Getdir or ChDir function species a non-existent disk.

16 Cannot remove current directory

Reported when trying to remove the currently active directory.

17 Cannot rename across drives

You cannot rename a le such that it would end up on another disk or partition.

100 Disk read error

An error occurred when reading from disk. Typically when you try to read past the end of a le.

101 Disk write error

Reported when the disk is full, and you're trying to write to it.

102 File not assigned

This is reported by Reset, Rewrite, Append, Rename and Erase, if you call them with an unassigned le as a parameter.

103 File not open

Reported by the following functions : Close, Read, Write, Seek, EOf, FilePos, FileSize, Flush, BlockRead, and BlockWrite if the le is not open.

104 File not open for input

Reported by Read, BlockRead, Eof, Eoln, SeekEof or SeekEoln if the le is not opened with Reset.

105 File not open for output

Reported by write if a text le isn't opened with Rewrite.

106 Invalid numeric format

Reported when a non-numeric value is read from a text le, when a numeric value was expected.

150 Disk is write-protected

(Critical error)

151 Bad drive request struct length

(Critical error)

152 Drive not ready

(Critical error)

154 CRC error in data

(Critical error)

156 Disk seek error

(Critical error)

157 Unknown media type

(Critical error)

158 Sector Not Found

(Critical error)

159 Printer out of paper

(Critical error)

160 Device write fault

(Critical error)

161 Device read fault

(Critical error)

162 Hardware failure

(Critical error)

200 Division by zero

The application attempted to divide a number by zero.

201 Range check error

If you compiled your program with range checking on, then you can get this error in the following cases:

1. An array was accessed with an index outside its declared range.
2. Trying to assign a value to a variable outside its range (for instance an enumerated type).

202 Stack overow error

The stack has grown beyond its maximum size (in which case the size of local variables should be reduced to avoid this error), or the stack has become corrupt. This error is only reported when stack checking is enabled.

203 Heap overow error

The heap has grown beyond its boundaries. This is caused when trying to allocate memory exlicitly with New, GetMem or ReallocMem, or when a class or object instance is created and no memory is left. Please note that, by default, Free Pascal provides a growing heap, i.e. the heap will try to allocate more memory if needed. However, if the heap has reached the maximum size allowed by the operating system or hardware, then you will get this error.

204 Invalid pointer operation

This you will get if you call Dispose or Freemem with an invalid pointer (notably, Nil)

205 Floating point overow

You are trying to use or produce too large real numbers.

206 Floating point underow

You are trying to use or produce too small real numbers.

207 Invalid oating point operation

Can occur if you try to calculate the square root or logarithm of a negative number.

210 Object not initialized

When compiled with range checking on, a program will report this error if you call a virtual method without having called istr constructor.

211 Call to abstract method

Your program tried to execute an abstract virtual method. Abstract methods should be overridden, and the overriding method should be called.

212 Stream registration error

This occurs when an invalid type is registered in the objects unit.

213 Collection index out of range

You are trying to access a collection item with an invalid index (objects unit).

214 Collection overow error

The collection has reached its maximal size, and you are trying to add another element (objects unit).

215 Arithmetic overow error

This error is reported when the result of an arithmetic operation is outside of its supported range. Contrary to Turbo Pascal, this error is only reported for 32-bit or 64-bit arithmetic overows. This is due to the fact that everything is converted to 32-bit or 64-bit before doing the actual arithmetic operation.

216 General Protection fault

The application tried to access invalid memory space. This can be caused by several problems:

1. Deferencing a nil pointer
2. Trying to access memory which is out of bounds (for example, calling move with an invalid length).

217 Unhandled exception occurred

An exception occurred, and there was no exception handler present. The sysutils unit installs a default exception handler which catches all excpetions and exits gracefully.

219 Invalid typecast

Thrown when an invalid typecast is attempted on a class using the as operator. This error is also thrown when an object or class is typecast to an invalid class or object and a virtual method of that class or object is called. This last error is only detected if the -CR compiler option is used.

227 Assertion failed error

An assertion failed, and no AssertErrorProc procedural variable was installed.