Gcc Error Message List
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…and How-to Solve The Problem1.1 Compilation Errors1.1.1 Error: …discards qualifiers1.1.2 Error: storage size of ‘foo' isn't known1.1.3 Error: gcc error message format multiple types in one declaration1.1.4 Error: invalid use of undefined gcc error messages type ‘struct Foo’1.1.5 Error: no matching function for call to ‘FooClass::foo()'1.1.6 Error: undefined reference to gcc #error ‘FooClass::foo()'1.1.7 Error: invalid operands of types `const char[31]' and `const char[7]' to binary `operator+'1.1.8 Error: `QValueList' undeclared (first use this function)1.1.9 Error: cannot call
Gcc Warnings
member function `Foo* Foo::instance() const' without object1.1.10 Errors: non-pointer type, non-aggregate type, cannot convert1.1.11 Error: syntax error before `*' token1.1.12 Error: `foo' is not a type1.1.13 Error: unable to find a register to spill in class `FOO'1.1.14 Error: invalid operands to binary ‘operator<<‘1.2 Qt Peculiarities1.2.1 Using Qt - invalid use gcc options of void expression1.2.2 Using Qt - …before ‘protected’1.2.3 Using Qt - …vtable1.3 Serious Warnings1.3.1 Warning: Control reaches the end of a non-void function1.3.2 Warning: ‘foo’ is used uninitialized in this function1.3.3 Warning: cannot pass objects of non-POD type ‘struct std::string' through ‘…' This page has been converted from a Wiki formatted article. If I've missed anything in the conversion process, please tell. Sometimes GCC emits something that can be described as Haiku poems - and you have no clue as to what it really is complaining about. This page is a collection of such gems, their meaning in English and how to solve the problem. If you run into an error that you feel belongs here, feel free to mail me. I'm using GMail as e8johan. Compilation Errors This is a list of compilation errors that you might find yourself trying to interpret in no particular orde
to stderr (the standard error file) and have the following form: e.adb:3:04: Incorrect spelling of keyword "function" e.adb:4:20: ";" should be "is" The first integer after the file name is the line number in the file, and the second integer is the column number within the line. GPS can parse the error messages and point to the referenced character. The following switches provide control over the error message format: -gnatv The v stands for verbose. The effect of this setting is to write long-format error messages to stdout (the standard output file. The same program compiled with the `-gnatv' switch would generate: 3. funcion X (Q : Integer) | >>> Incorrect spelling of keyword "function" 4. return http://digitalfanatics.org/resources/gcc-error-messages/ Integer; | >>> ";" should be "is" The vertical bar indicates the location of the error, and the >>> prefix can be used to search for error messages. When this switch is used the only source lines output are those with errors. -gnatl The l stands for list. This switch causes a full listing of the file to be generated. In the case where a body is compiled, the corresponding spec is also listed, https://gcc.gnu.org/onlinedocs/gnat_ugn/Output-and-Error-Message-Control.html along with any subunits. Typical output from compiling a package body p.adb might look like: Compiling: p.adb 1. package body p is 2. procedure a; 3. procedure a is separate; 4. begin 5. null | >>> missing ";" 6. end; Compiling: p.ads 1. package p is 2. pragma Elaborate_Body | >>> missing ";" 3. end p; Compiling: p-a.adb 1. separate p | >>> missing "(" 2. procedure a is 3. begin 4. null | >>> missing ";" 5. end; When you specify the `-gnatv' or `-gnatl' switches and standard output is redirected, a brief summary is written to stderr (standard error) giving the number of error messages and warning messages generated. -gnatl=`fname' This has the same effect as `-gnatl' except that the output is written to a file instead of to standard output. If the given name fname does not start with a period, then it is the full name of the file to be written. If fname is an extension, it is appended to the name of the file being compiled. For example, if file xyz.adb is compiled with `-gnatl=.lst', then the output is written to file xyz.adb.lst. -gnatU This switch forces all error messages to be preceded by the unique string 'error:'. This means that error messages take a few more characters in space, but allows easy sea
source file, and ":30:" is the line number where the error was located. The "undeclared" error is a common mistake. All variables must be declared before they are used, and if you forget, http://users.csc.calpoly.edu/~jdalbey/101/Resources/errormessages.html you'll see this error. It means the compiler didn't find a declaration for http://web.ics.purdue.edu/~cs240/misc/errors.html a variable prior to its first use. The error can also occur if you spelled the variable name differently in two places. The compiler is "case-sensitive" so "DOG" and "dog" are two different variables; pay careful attention to upper and lower case letters. /tmp/ccJiZokm.o: In function `main': conepainting.c:(.text+0x63): undefined reference to gcc error `sqrt' collect2: ld returned 1 exit status You forgot to compile with the math library. Provide the "-lm" flag (that's the letter "l" not the numeral "1" to the compiler, like this: gcc -lm conepainting.c no newline at end of file. Be sure there is a new line with no blank spaces as the last line in the file. warning: implicit declaration of gcc error message function `printf' You must have a #include
can easily range from 50 to 75 percent of the total development cost."1 While this is not a course about the software development life cycle it is our goal to teach you good software development technique. The errors that you typically experience are one of three types: Compiler Errors Linker Errors Run Time Errors lets examine these three types of errors in more detail. Compiler Errors Compiler errors are caused by incorrect syntax. This means that you have not followed the basic rules of C. These basic rules are things like: putting a semicolon at the end of a line writing a proper function header passing the correct number and type of arguments to a function matching up all pairs of braces {} and parentheses () not using variables that you haven't declared declaring all variables at the top of a function many, many more When you run the compiler on your code it first does any preprocessing (that is any line that begins with #). Then it checks the syntax of your code. In other words it makes sure that you have followed all the rules of C. If you haven't it prints out an error so that you can fix your syntax. Unfortunately most new users find the messages sent back from gcc confusing. So we will go over some common gcc error messages, what they mean, and how to fix them. General compile-time error and warning description In C, a compilation error is usually fatal, meaning that the C compiler cannot compile the source code. A warning, on the other had, is usually just that. The compiler has identified that there may be a problem, but it can produce object code anyway. Warnings should not be ignored, because they usually do indicate that there is something wrong with the program, and it is likely to behave differently from what you would expect. Error messages and warnings are preceded by the program file name and function in which the error was encountered. For example, prog.c: In function `main': indicates that the error was encountered in the program file prog.c, and specifically in function main. The next lines indicate the errors/warnings that occur in that function and program file. If the program is multi-function and/or multi-file, then each different function/file containing errors will be listed separately. The warning/error lines following the function/program file identification line is a record of the program file containing the error; the line number in the source file at which the error occurred; the string "warning", if the message is just a warning (nothing is printed if it i