Invocation commands

The xlc utility provides two basic compiler invocation commands, xlc and xlC (xlc++), along with several other compiler invocation commands to support various C/C++ language levels and compilation environments. In most cases, you would use the xlc command to compile C source files and xlC (xlc++) command to compile C++ source files.

You can however, use other forms of the command if your particular environment requires it. The various compiler invocation commands for C are:

• xlc
• cc
• c89
• c99
• xlc_x
• cc_x
• c89_x
• c99_x
• xlc_64
• cc_64
• c89_64
• c99_64

The various compiler invocation commands for C++ are:

• xlC (xlc++)
• cxx
• c++
• xlC_x (xlc++_x)
• c++_x
• cxx_x
• xlC_64 (xlc++_64)
• c++_64
• cxx_64

The two basic compiler invocation commands appear as the first entry of each of these list items. Select an invocation command using the following criteria:

xlc

Invokes the compiler for C source files with a default language level of ANSI, the compiler option -qansialias to allow type-based aliasing, and the compiler option -qcpluscmt to allow C++ style comments (//).

xlC (xlc++)

Invokes the compiler so that source files are compiled as C++ language source code.

Files with .c suffixes, assuming you have not used the -+ compiler option, are compiled as C language source code with a default language level of ANSI, and compiler option -qansialias to allow type-based aliasing.

If any of your source files are C++, you must use this invocation to link with the correct runtime libraries.

cc

Invokes the compiler for C source files with a default language level of extended and compiler options -qnoro and -qnoroconst (to provide placement of string literals or constant values in read/write storage).

Use this invocation for legacy C code that does not require compliance with ANSI C. This invocation is intended to provide the same compiler behavior as when invoked by the cc command name of the c89 utility.

c89

Invokes the compiler for C source files, with a default language level of ANSI, and specifies compiler options -qansialias (to allow type-based aliasing) and -qnolonglong (disabling use of long long). Use this invocation for strict conformance to the ISO/IEC 9899:1990 standard. This invocation is intended to provide the same compiler behavior as when invoked by the c89 command name of the c89 utility.

c99

Invokes the compiler for C source files, with a default language level of STDC99 and specifies compiler option -qansialias (to allow type-based aliasing). Use this invocation for strict conformance to the ISO/IEC 9899:1999 standard.

cxx/c++

The cxx and c++ commands invoke the compiler for C++ language source code. Both are intended to provide the same compiler behavior as when invoked using the cxx and c++ command names of the c89 utility.

You can combine the previously described command names with the following suffixes:

_x

Command invocations using command names with suffix _x are the same as invocations using names without suffixes, except the -qxplink option is also specified and appropriate XPLINK libraries are used in the link step. If you are building an XPLINK application, you no longer need to use command names with suffix _x to link with the correct runtime libraries. This can be achieved through the new configuration attributes that have been introduced to enable XPLINK behavior without the use of suffixes. See Configuration file attributes for further information.

_64

Command invocations using command names with suffix _64 are the same as invocations using names without suffixes, except the -q64 option is also specified and appropriate 64-bit libraries are used in the link step. If you are building a 64-bit application, you no longer need to use command names with suffix _64 to link with the correct runtime libraries. This can be achieved through the new configuration attributes that have been introduced to enable 64-bit behavior without the use of suffixes. See Configuration file attributes for further information.