Compiler Error Messages
During the program compilation three types of errors can arise:
Compiler Warnings:
The warnings don't stop the compilation, just alert the user some non-recommended and error-prone operation is attempted in the code.
Sometimes one of these operations is coded deliberately to achieve a result, in this case the warnings can be disabled by setting the -w 1 option at the command line.

- 1 Passing scalar as pointer
- 2 Passing pointer to scalar
- 3 Passing different pointer types
- 4 Suspicious pointer assignment
- 5 Implicit conversion
- 6 Cannot export symbol without -export option
- 7 Identifier's name too big, truncated
- 8 Literal number too big, truncated
- 9 Literal string too big, truncated
- 10 UDT with pointer or var-len string fields
- 11 UDT with var-len string fields
- 12 Implicit variable allocation
- 13 Missing closing quote in literal string
- 14 Function result was not explicitly set
- 15 Branch crossing local variable definition
- 16 No explicit BYREF or BYVAL
- 17 Possible escape sequence found in
- 18 The type length is too large, consider passing BYREF
- 19 The length of the parameters list is too large, consider passing UDT's BYREF
- 20 The ANY initializer has no effect on UDT's with default constructors
- 21 Object files or libraries with mixed multithreading (-mt) options
- 22 Object files or libraries with mixed language (-lang) options
- 23 Deleting ANY pointers is undefined
- 24 Array too large for stack, consider making it var-len or SHARED
- 25 Overflow in constant conversion
- 26 Variable following NEXT is meaningless
- 27 Cast to non-pointer
- 28 Return method mismatch
- 29 Passing Pointer
- 30 Command line option overrides directive
- 31 Directive ignored after first pass
- 32 'IF' found directly after multi-line 'ELSE'
- 33 Shift value greater than or equal to number of bits in data type

Compiler Error messages:
The error messages stop the compilation after 10 errors (see the -maxerr command-line option to change that default value) or a fatal error occurred, and require a correction by the user before the compilation can be continued. The compiler signals the lines where the errors have been found, so the correction can be done quickly. In a few cases the place pointed at by the error messages is not where the errors can be found, it's the place where the compiler has given up in waiting for something that should be somewhere.

- 1 Argument count mismatch
- 2 Expected End-of-File
- 3 Expected End-of-Line
- 4 Duplicated definition
- 5 Expected 'AS'
- 6 Expected '('
- 7 Expected ')'
- 8 Undefined symbol
- 9 Expected expression
- 10 Expected '='
- 11 Expected constant
- 12 Expected 'TO'
- 13 Expected 'NEXT'
- 14 Expected identifier
- 15 Internal: Tables Full!
- 16 Expected '-'
- 17 Expected ','
- 18 Syntax error
- 19 Element not defined
- 20 Expected 'END TYPE' or 'END UNION'
- 21 Type mismatch
- 22 Internal!
- 23 Parameter type mismatch
- 24 File not found
- 25 Invalid data types
- 26 Invalid character
- 27 File access error
- 28 Recursion level too deep
- 29 Expected pointer
- 30 Expected 'LOOP'
- 31 Expected 'WEND'
- 32 Expected 'THEN'
- 33 Expected 'END IF'
- 34 Illegal 'END'
- 35 Expected 'CASE'
- 36 Expected 'END SELECT'
- 37 Wrong number of dimensions
- 38 'SUB' or 'FUNCTION' without 'END SUB' or 'END FUNCTION'
- 39 Expected 'END SUB' or 'END FUNCTION'
- 40 Illegal parameter specification
- 41 Variable not declared
- 42 Variable required
- 43 Illegal outside a compound statement
- 44 Expected 'END ASM'
- 45 Function not declared
- 46 Expected ';'
- 47 Undefined label
- 48 Too many array dimensions
- 49 Expected scalar counter
- 50 Illegal outside a CONSTRUCTOR, DESTRUCTOR, FUNCTION, OPERATOR, PROPERTY or SUB block
- 51 Expected var-len array
- 52 Fixed-len strings cannot be returned from functions
- 53 Array already dimensioned
- 54 Illegal without the -ex option
- 55 Type mismatch
- 56 Illegal specification
- 57 Expected 'END WITH'
- 58 Illegal inside functions
- 59 Expected array
- 60 Expected '{'
- 61 Expected '}'
- 62 Too many expressions
- 63 Expected explicit result type
- 64 Range too large
- 65 Forward references not allowed
- 66 Incomplete type
- 67 Array not dimensioned
- 68 Array access, index expected
- 69 Expected 'END ENUM'
- 70 Var-len arrays cannot be initialized
- 71 Invalid bitfield
- 72 Too many parameters
- 73 Macro text too long
- 74 Invalid command-line option
- 75 Var-len strings cannot be initialized
- 76 Recursive TYPE or UNION not allowed
- 77 Recursive DEFINE not allowed
- 78 Array fields cannot be redimensioned
- 79 Identifier cannot include periods
- 80 Executable not found
- 81 Array out-of-bounds
- 82 Missing command-line option for
- 83 Math overflow
- 84 Expected 'ANY'
- 85 Expected 'END SCOPE'
- 86 Illegal inside a compound statement or scoped block
- 87 UDT function results cannot be passed by reference
- 88 Ambiguous call to overloaded function
- 89 No matching overloaded function
- 90 Division by zero
- 91 Cannot pop stack, underflow
- 92 UDT's containing var-len string fields cannot be initialized
- 93 Branching to scope block containing local variables
- 94 Branching to other functions or to module-level
- 95 Branch crossing local array, var-len string or object definition
- 96 LOOP without DO
- 97 NEXT without FOR
- 98 WEND without WHILE
- 99 END WITH without WITH
- 100 END IF without IF
- 101 END SELECT without SELECT
- 102 END SUB or FUNCTION without SUB or FUNCTION
- 103 END SCOPE without SCOPE
- 104 END NAMESPACE without NAMESPACE
- 105 END EXTERN without EXTERN
- 106 ELSEIF without IF
- 107 ELSE without IF
- 108 CASE without SELECT
- 109 Cannot modify a constant
- 110 Expected period ('.')
- 111 Expected 'END NAMESPACE'
- 112 Illegal inside a NAMESPACE block
- 113 Symbols defined inside namespaces cannot be removed
- 114 Expected 'END EXTERN'
- 115 Expected 'END SUB'
- 116 Expected 'END FUNCTION'
- 117 Expected 'END CONSTRUCTOR'
- 118 Expected 'END DESTRUCTOR'
- 119 Expected 'END OPERATOR'
- 120 Expected 'END PROPERTY'
- 121 Declaration outside the original namespace
- 122 No end of multi-line comment, expected "'/"
- 123 Too many errors, exiting
- 124 Expected 'ENDMACRO'
- 125 EXTERN or COMMON variables cannot be initialized
- 126 At least one parameter must be a user-defined type
- 127 Parameter or result must be a user-defined type
- 128 Both parameters can't be of the same type
- 129 Parameter and result can't be of the same type
- 130 Invalid result type for this operator
- 131 Invalid parameter type, it must be the same as the parent TYPE/CLASS
- 132 Vararg parameters are not allowed in overloaded functions
- 133 Illegal outside an OPERATOR block
- 134 Parameter cannot be optional
- 135 Only valid in -lang
- 136 Default types or suffixes are only valid in -lang
- 137 Suffixes are only valid in -lang
- 138 Implicit variables are only valid in -lang
- 139 Auto variables are only valid in -lang
- 140 Invalid array index
- 141 Operator must be a member function
- 142 Operator cannot be a member function
- 143 Member function not allowed in anonymous UDT's
- 144 Expected operator
- 145 Declaration outside the original namespace or class
- 146 A destructor should not have any parameters
- 147 Expected class or UDT identifier
- 148 Var-len strings cannot be part of UNION's or nested TYPE's
- 149 Fields with constructors cannot be part of UNION's or nested TYPE's
- 150 Fields with destructors cannot be part of UNION's or nested TYPE's
- 151 Illegal outside a CONSTRUCTOR block
- 152 Illegal outside a DESTRUCTOR block
- 153 UDT's with methods must have unique names
- 154 Parent is not a class or UDT
- 155 Call to another constructor must be the first statement
- 156 The constructor or destructor calling convention must be CDECL
- 157 This symbol cannot be undefined
- 158 Either 'RETURN' or 'FUNCTION =' should be used when returning objects with default constructors
- 159 Invalid assignment/conversion
- 160 Invalid array subscript
- 161 TYPE or CLASS has no default constructor
- 162 Invalid priority attribute
- 163 PROPERTY GET should have no parameter, or just one if indexed
- 164 PROPERTY SET should have one parameter, or just two if indexed
- 165 Expected 'PROPERTY'
- 166 Illegal outside a PROPERTY block
- 167 PROPERTY has no GET method/accessor
- 168 PROPERTY has no SET method/accessor
- 169 PROPERTY has no indexed GET method/accessor
- 170 PROPERTY has no indexed SET method/accessor
- 171 Missing overloaded operator:
- 172 The NEW[] operator does not allow explicit calls to constructors
- 173 The NEW[] operator only supports the { ANY } initialization
- 174 The NEW operator cannot be used with strings
- 175 Illegal member access
- 176 Expected ':'
- 177 The default constructor has no public access
- 178 Constructor has no public access
- 179 Destructor has no public access
- 180 Illegal non-static member access
- 181 Member cannot be static
- 182 Member isn't static
- 183 Only static members can be accessed from static functions
- 184 The PRIVATE and PUBLIC attributes are not allowed with REDIM, COMMON or EXTERN
- 185 The function prototype wasn't declared as STATIC
- 186 This operator cannot be STATIC
- 187 Parameter must be an integer
- 188 Parameter must be a pointer
- 189 Expected initializer
- 190 Fields cannot be named as keywords in TYPE's that contain member functions or in CLASS'es
- 191 Illegal outside a FOR compound statement
- 192 Illegal outside a DO compound statement
- 193 Illegal outside a WHILE compound statement
- 194 Illegal outside a SELECT compound statement
- 195 Expected 'FOR'
- 196 Expected 'DO'
- 197 Expected 'WHILE'
- 198 Expected 'SELECT'
- 199 No outer FOR compound statement found
- 200 No outer DO compound statement found
- 201 No outer WHILE compound statement found
- 202 No outer SELECT compound statement found
- 203 Expected 'CONSTRUCTOR', 'DESTRUCTOR', 'DO', 'FOR', 'FUNCTION', 'OPERATOR', 'PROPERTY', 'SELECT', 'SUB' or 'WHILE'
- 204 Expected 'DO', 'FOR' or 'WHILE'
- 205 Illegal outside a SUB block
- 206 Illegal outside a FUNCTION block
- 207 Ambiguous symbol access, explicit scope resolution required
- 208 An ENUM, TYPE or UNION cannot be empty
- 209 ENUM's declared inside EXTERN .. END EXTERN blocks don't open new scopes
- 210 Only member functions can be static
- 211 Invalid initializer
- 212 Objects with default [con|de]structors or methods are only allowed in the module level
- 213 Symbol not a CLASS, ENUM, TYPE or UNION type
- 214 Too many elements
- 215 Only data members supported
- 216 UNIONs are not allowed
- 217 Arrays are not allowed
- 218 COMMON variables cannot be object instances of CLASS/TYPE's with cons/destructors
- 219 Cloning operators (LET, Copy constructors) can't take a byval arg of the parent's type
- 220 Local symbols can't be referenced
- 221 Expected 'PTR' or 'POINTER'
- 222 Too many levels of pointer indirection
- 223 Dynamic arrays can't be const
- 224 Non-const UDT cannot invoke const method
- 225 Elements must be empty for strings and arrays
- 226 GOSUB disabled, use 'OPTION GOSUB' to enable
- 227 Invalid -lang
- 228 Can't use ANY as initializer in array with ellipsis bound
- 229 Must have initializer with array with ellipsis bound
- 230 Can't use ... as lower bound

Third party programs errors
These errors occur after the source has been compiled into assembler, they come from the auxiliary programs FB requires to compile a source into an executable: the linker, the assembler and (for Windows programs) the resource compiler.
If an IDE or a make utility are been used, additional errors can arise. These errors are outside the scope of this help.