Setting Compiler and Linker Options

Setting Compiler and Linker Options for All Build Targets

To set compiler and linker options for all build targets:

1. Click the Project Inspector button in the project window, and choose Build Attributes from the pop-up menu at the top of the Inspector.
2. Edit the fields Compiler Flags and Linker Flags.

Here are some useful compiler flags:

Flag	Description
-ansi	Uses strict ANSI C syntax.
-traditional	Uses the traditional C syntax, described in Kernigan & Ritchie's The C Language.
-bsd	Uses strict BSD syntax.
-pointer-arith	Warns you if you use pointer arithmetic on a void pointer or a function pointer.
-finline-functions	Makes all simple functions inline.
-pipe	Uses pipes in place of temporary intermediate files.

Here are some useful linker flags:

Flag	Description
-sectorder	Orders the blocks in a specified section.
-undefined	Specifies how undefined symbols are treated: as errors, warnings, or ignored.
-whyload	Prints why each member of a library is loaded.
-ysym	For a given symbol, prints the names of the files that reference it.
-Yn	For the first n undefined symbols, prints the names of the files that referenced it.

Setting Search Paths

You can choose additional directories where the compiler and linker search for header files, frameworks, and libraries. This is useful when your project contains a library or framework that is not in one of the standard search paths.

To modify the search paths:

1. Click the Project Inspector button in the project window, and choose Build Attributes from the pop-up menu at the top of the Inspector.
2. Choose one of the following from the second pop-up menu on the Inspector: Library Search Order, Framework Search Order, or Header Search Order.

To add a directory to a search path:

• Click Set and choose the directory

  or

• Type a pathname in the text field under the list, and click Add.

To edit a directory in the search path:

• Click the directory, and click Set.

These are the standard directories that Project Builder always searches. You cannot remove them from the search paths.

Type of File	Search Order
Frameworks	/Local/Library/Frameworks/ /System/Library/Frameworks/
Header files	the project directory /Local/Developer/Headers/ /System/Developer/Headers/
Libraries	/lib /usr/lib/ /usr/local/lib

Setting Optimization Levels

You can choose how much the compiler optimizes your code. By default, the optimization option is set to -O1 . Project Build uses the optimization level whenever you build the default, install, or profile targets.

To set the optimization options:

• Open the Makefile.postamble file, which is in the Suporting Files suitcase, and edit the value of OPTIMIZATION_CFLAG .

  For example, this line sets the sets the optimization level to -O2 :

  OPTIMIZATION_CFLAG = -O2

Here are some useful values for OPTIMIZATION_CFLAG :

Flag	Description
-O0	No optimization.
-O or -O1	Performs the following optimizations: * Allocates variables to registers using its own judgement, and ignoring the register keyword. * Optimizes branches.
-O2	Performs all the optimizations that -O1 does, plus: * Eliminates common sub-expressions. * Performs strength reduction.
-O3	Performs all the optimizations that -O2 does, plus: * Unrolls loops.

Setting Debug Options

You can choose how much debugging information the compiler puts into your code. By default, the debug option is set to -g. Project Builder uses the debug options whenever you build the debug target.

To set the debug level level:

• Open the Makefile.postamble file, which is in the Suporting Files suitcase, and edit the value of DEBUG_BUILD_FLAGS .

Here are some useful values for DEBUG_BUILD_FLAGS , if you're compiling for Mac OS X:

Flag	Description
-g	Produces general debug information.
-gstabs	Produces debugging information in stabs format, without GDB extensions.
-gstabs+	Produces debugging information in stabs format, with GDB extensions.

Here are some useful values for DEBUG_BUILD_FLAGS , if you're compiling for Windows NT or Windows98:

Flag	Description
-g1	Produces minimal degugging information, including information on functions and external variables.
-g or -g2	Produces all the debugging information that -g1 does, plus information on line numbers and internal variables.
-g3	Produces all the debugging information that -g1 does, plus information on macros.

Project Builder's debugger GDB lets you debug optimized code. This is useful if you're experiencing a bug that only appears when you optimize your code. By default, the debug target does not optimize. To debug an optimized project:

• Change the definition of DEBUG_BUILD_FLAGS to be the following:

  DEBUG_BUILD_FLAGS = $(OPTIMIZATION_CFLAG) -g

Setting Warning Options

You can choose which warnings the compiler displays. Project Build uses the warnings options whenever you build the default, install, degug, or profile targets. By default, it uses the -Wmost option which warns against the most common errors but not against other constructions that are reasonable in some situations.

To set the warning options:

• Open the Makefile.postamble file, which is in the Suporting Files suitcase, and edit the value of WARNING_CFLAG .

For example, to add pointer arithmetic to the list of things the compiler warns you about, use the following:

WARNING_CFLAG = -Wall -Wpointer-arith

Here are some useful values for WARNING_CFLAG :

Flag	Description
-Wpointer-arith	Warns you if you use pointer arithmetic on a void pointer or a function pointer.
-Wstrict-prototypes	Warns you if you define or declare a function without specifying its argument types.
-Wmissing-prototypes	Warns you if you define a global function is defined without a prototype declaration.
-Winline	Warns you if the cmpiler cannot inline a function which you declared as inline or which the optimizer tried to inline.