Are you having a GCC/G++ Compiler Error?

If you answered YES!!!!! Then you have found the right place. This page is
constantly growing page. It is meant to be a resource for CS students at
Spelman College to help them figure out compiler errors when no help can
be found.

Errors and Warnings?

The G++ compiler produces both warnings and errors. There is a reason
for these two types of diagnostics:

     Errors: These messages are problems that make it impossible for you to
     compile your program. They are reported giving you both the file name where
     the error was found and the line number of the error:

SourceFile.cc:17:   - indicates the error is on line #17 of the

file called SourceFile

     Warnings: These messages indicated some unusual condition in your code.
     It is possible that it may cause an actual error(in your case it will most likely
     cause an error).  The compilation process will usually continue until an
     error is uncovered.   Warning message look just like error messages, but will
     have the word warning at the beginning of the message:

SourceFile.cc:17: warning   -  indicates a warning on line #17 of

the file called SourceFile

     If you give the compiler the -Wall or -W option then it will provide all warnings.
     Otherwise, only the more harmful warnings are displayed.

When should you use this page?

You should use this page as a first resort when you can not figure out
what a compiler error message means. If you still can't figure it out,
then this document may help you understand the response you get
from a peer, the TA, or your professor.

How to use this page?

Well for now(in the future in my copious spare time this may be
more sophisticated), you have to do the following:

• Pick the error message you want to know about(The best way to do
  this is to pick the very first error message...especially if there is a whole ton of em!)
• Browse the list of error messages and match one to the message you are getting
• Click on the selected message
• Try to fix your problem based on the information for that message
• If you don't see your error message and a friend can't help you send a message to hardnett@spelman.edu.

Which error message is yours?

Listing of Compiler Error Explanations
(NOTE: This listing only contains
the beginning of the error message)

Compiler Error Messages(Parsing, Type Checking, etc.)
Linker Error Messages(Final stage of the compilation process)

• Undefined first referenced symbol in file main /usr/local/lib/.../crt1.o ld:fatal: Symbol referencing errors...
  
• Somefile:#: syntax error before 'some symbols'
• Somefile:#: warning: ANSI C++ forbids declaration 'SomeIdentifier' with no type or storage class
  
• Somefile:#: 'SomeIdentifier' undeclared (first use this function)

Somefile:#: (each undeclared identifier is reported only once Somefile:#:
for each function it appears in.)

• Somefile:#: type specifier omitted for parameter Somefile.cc: In method 'YourClass::TheMethod(...)'

---

The following group of messages all begin with:

In file included from somefile.cc:#: somefile.h:#:

all of this stuff basically means that the file that is giving you problems was #included
in the file somefile.h which was #included in the file somefile.cc.(sometimes this is
useful information)

• Somefile: #: warning: implicit declaration of function 'SomeFunction'
• ... missingfile.h: No such file or directory
• ... culprit.h:X: redefinition of 'some program structure'    culprit.h:X-1: previous definition here
• ... firstfile.h:#: conflicting types for `typedef  OldType NewType'    secondfile.h: previous declaration as 'typedef AnothaOldType NewType'
  

Back to the Class Page