None.
Passes the listed options to a component that is executed during compilation.
.-----------. V | >>- -W--+-a-+----,--option-+----------------------------------->< +-b-+ +-c-+ +-C-+ +-d-+ +-E-+ +-f-+ +-I-+ +-L-+ +-l-+ +-m-+ '-p-'
The following table shows the correspondence between -W parameters and the component executable names:
| Parameter | Description | Executable name |
|---|---|---|
| a | Assembler | as |
| b | Low-level optimizer | xlCcode |
| c | Compiler front end | xlcentry, xlCentry |
C |
C++ compiler front end | xlCentry |
| d | Disassembler | dis |
| E | CreateExportList utility | CreateExportList |
f |
c++filt utility | c++filt |
| I | High-level optimizer, compile step | ipa |
| L | High-level optimizer, link step | ipa |
| l | Linker | ld |
m |
Linkage helper | munch |
| p | Preprocessor | n/a |
In the string following the -W option, use a comma as the separator for each option, and do not include any spaces. If you need to include a character that is special to the shell in the option string, precede the character with a backslash. For example, if you use the -W option in the configuration file, you can use the escape sequence backslash comma (\,) to represent a comma in the parameter string.
You do not need the -W option to pass most options to the linker ld; unrecognized command-line options, except -q options, are passed to it automatically. Only linker options with the same letters as compiler options, such as -v or -S, strictly require -W.
By default, static objects are initialized in the order of priority specified by #pragma priority or the -qpriority (C++ only) option. You can use -Wm option to control the initialization order of the objects with the same priorities. Specifying -Wm -c instructs the compiler to initialize object files with the same priority in the order in which the files were given on the command line during linking into the library and the static objects within the files are initialized according to their declaration order.-Wm -r option, however, specifies that the object files with the same priority are to be initialized in the opposite order in which they were encountered during the linking phase.
None.
xlc -Wl,-berok file.c
xlc -Wa,-x -Wl,-s produces_warnings.s uses_many_symbols.c