In general, if more than one variation of the same option is specified (with the exception of -qxref and -qattr), the compiler uses the setting of the last one specified. Compiler options specified on the command line must appear in the order you want the compiler to process them.
Two exceptions to the rules of conflicting options are the -Idirectory and -Ldirectory options, which have cumulative effects when they are specified more than once.
Not all option conflicts are resolved using the preceding rules. The following table summarizes exceptions and how the compiler handles conflicts between them. Rules for resolving conflicts between compiler mode and architecture-specific options are discussed in Specifying compiler options for architecture-specific, 32-bit or 64-bit compilation.
| Option | Conflicting options | Resolution |
|---|---|---|
| -qalias=allptrs | -qalias=noansi | -qalias=noansi |
| -qalias=typeptr | -qalias=noansi | -qalias=noansi |
| -qhalt | Multiple severities specified by -qhalt | Lowest severity specified |
| -qnoprint | -qxref, -qattr, -qsource, -qlistopt, -qlist | -qnoprint |
| -qfloat=rsqrt | -qnoignerrno | Last option specified |
| -qxref | -qxref=full | -qxref=full |
| -qattr | -qattr=full | -qattr=full |
| -qfloat=hsflt | -qfloat=spnans | -qfloat=hsflt |
| -qfloat=hssngl | -qfloat=spnans | -qfloat=hssngl |
| -E | -P, -o, -S | -E |
| -P | -c, -o, -S | -P |
| -# | -v | -# |
| -F | -B, -t, -W, -qpath | -B, -t, -W, -qpath |
| -qpath | -B, -t | -qpath |
| -S | -c | -S |
| -qnostdinc | -qc_stdinc, -qcpp_stdinc | -qnostdinc |