Remarks

Remark messages report common but sometimes unconventional use of C or C++. The compiler does not print or display remarks unless you specify the /W4 option. Remarks do not stop translation or linking. Remarks do not interfere with any output files. The following are some representative remark messages:

•       function declared implicitly

•       type qualifiers are meaningless in this declaration

•       controlling expression is constant

Warnings

Warning messages report legal but questionable use of the C or C++. The compiler displays warnings by default. You can suppress all warning messages with the /w compiler option. Warnings do not stop translation or linking. Warnings do not interfere with any output files. The following are some representative warning messages:

•       declaration does not declare anything

•       pointless comparison of unsigned integer with zero

•       possible use of = where == was intended

Errors

These messages report syntactic or semantic misuse of C or C++. The compiler always displays error messages. Errors suppress object code for the module containing the error and prevent linking, but they allow parsing to continue to detect other possible errors. Some representative error messages are:

•       missing closing quote

•       expression must have arithmetic type

•       expected a ";"

Option Summary

Use the following compiler options to control remarks, warnings, and errors:

You can also control the display of diagnostic information with variations of the /Qdiag compiler option. This compiler option accepts numerous arguments and values, allowing you wide control over displayed diagnostic messages and reports.

Some of the most common variations include the following:

The list items can be specific diagnostic IDs, one of the keywords warn, remark, or error, or a keyword specifying a certain group (par, vec, sc, driver, thread, par, port-linux,, sc,openmp).

Other diagnostic-related options include the following:

The sentinel attribute is described in the GNU* documentation here: http://gcc.gnu.org/onlinedocs/gcc-4.4.1/gcc/Function-Attributes.html#Function-Attributes 

It says:

A valid NULL in this context is defined as zero with any pointer type. If your system defines the NULL macro with an integer type then you need to add an explicit cast.

The GNU compiler will give a diagnostic too also if "-Wformat" is specified.

Example:

#define NULL 0

//#define NULL ((void*)0)  // this fixes the problem

int execl(const char *path, const char *arg, ...) __attribute__ ((sentinel));

int main() {
   execl("","",NULL); // warning issued here
   return 0;
}

$ icc -c diag1881.c
diag1881.c(9): warning #1881: argument must be a constant null pointer value
     execl("","",NULL); // warning issued here
                 ^

Resolution status:
Use a header file that defines NULL as a pointer type (such as stddef.h) or declare NULL correctly like:

#define NULL ((void*)0)  // this fixes the problem

Cause:

This warning is issued by the driver when you have two conflicting options on the same command line. The last one on the command line "wins".Remember that command line options can exist in makefiles and config files (i.e. icc.cfg, icpc.cfg, icl.cfg or ifort.cfg).

Example:

> icc -O3 -O2 -c foo.c
icc: command line warning #10120: overriding '-O3' with '-O2'

Resolution Status:

Look at your command line and remove the redundant flag.

The Intel(R) C++ compiler for Windows needs to know which version of the Microsoft* compiler (i.e. Microsoft Visual C++ 2003*, 2005*, 2008* etc) you are using in order to set our Microsoft compability version to emulate.

For example, there are certain Microsoft bugs that exist in the Microsoft Visual C++ 2003 compiler but were fixed in Microsoft Visual C++ 2005 that we would only emulate if you had a Microsoft Visual C++ 2003 environment (header files and libraries).

In order to do this, the icl driver looks in your path for the version of cl.exe and sets the microsoft version when it calls our compiler based upon what it finds.

Example:

Compiling any program on Windows and not having "cl.exe" somewhere in your path.

Resolution status:

Change your path environment variables to include the directories where Microsoft Visual C++ executable "cl.exe", include header files and run time libraries. Easiest way is to run Visual C++ vcvars32.bat.

Or pass the options "/Qvc[7.1|8|9]" and "/Qlocation,link,"[cl-dir]" to the icl.exe.