HP aC++/HP C A.06.28 Programmer's Guide Integrity servers (769150-001, March 2014)

Table 3 Size and Alignment of HP Compiler Data Types (continued)

AlignmentSize (in bytes)Data Type

*** struct and union alignment are same and follow strict alignment of any member. Padding is done to a multiple

of the alignment size.

-fshort-enums

cc -Agcc -Wc,--fshort-enums foo.c

aCC -Ag++ -Wc,--fshort-enums foo.c

The -fshort-enums option is used with the -Agcc or -Ag++ options to cause each enum type

to be represented using the smallest integer type that is capable of representing all values of the

enum type. Because it changes the representation of types, the code generated is not binary

compatible with code compiled without the option. The primary use of this option is for compatibility

with gcc, but it can provide performance improvement to applications that can accept the binary

incompatibility.

+unum

The +unum option allows pointers to access non-natively aligned data. This option alters the way

that the compiler accesses dereferenced data. Use of this option may reduce the efficiency of

generated code. Specify num as 1, 2, or 4, as follows:

1 - Assume single byte alignment. Dereferences are performed with a series of single-byte loads

and stores.

2 - Dereferences are performed with a series of two-byte loads and stores.

4 - Dereferences are performed with a series of four-byte loads and stores.

Example:

aCC +u1 app.C

Debugging Options

Debugging options enable you to use the HP WDB debugger.

Information on HP WDB is available at this location: http://www.hp.com/go/wdb

The +d option prevents the expansion of inline functions. It is useful when you debug code because

breakpoints cannot be set at inline functions. Using the +d option disables all inlining. It is mapped

to the +inline_level 0 option.

+expand_types_in_diag

The +expand_types_in_diag option expands typedefs in diagnostics so that both the original

and final types are present.

-g

The -g option causes the compiler to generate minimal information for the debugger. It uses an

algorithm that attempts to reduce duplication of debug information.

To suppress expansion of inline functions, use the +d option.

-g0

The -g0 option causes the compiler to generate full debug information for the debugger.

Debugging Options 35