Data Options

This section contains descriptions for compiler options that pertain to the treatment of data.

• align
  Determines whether variables and arrays are naturally aligned.
• auto-ilp32, Qauto-ilp32
  Instructs the compiler to analyze the program to determine if there are 64-bit pointers that can be safely shrunk into 32-bit pointers and if there are 64-bit longs (on Linux* systems) that can be safely shrunk into 32-bit longs.
• auto-p32
  Instructs the compiler to analyze the program to determine if there are 64-bit pointers that can be safely shrunk to 32-bit pointers.
• check-pointers, Qcheck-pointers
  Determines whether the compiler checks bounds for memory access through pointers.
• check-pointers-dangling, Qcheck-pointers-dangling
  Determines whether the compiler checks for dangling pointer references.
• check-pointers-mpx, Qcheck-pointers-mpx
  Determines whether the compiler checks bounds for memory access through pointers on processors that support Intel® Memory Protection Extensions (Intel® MPX).
• check-pointers-narrowing, Qcheck-pointers-narrowing
  Determines whether the compiler enables or disables the narrowing of pointers to structure fields.
• check-pointers-undimensioned, Qcheck-pointers-undimensioned
  Determines whether the compiler checks bounds for memory access through arrays that are declared without dimensions.
• falign-functions, Qfnalign
  Tells the compiler to align functions on an optimal byte boundary.
• falign-loops, Qalign-loops
  Aligns loops to a power-of-two byte boundary.
• falign-stack
  Tells the compiler the stack alignment to use on entry to routines. This option is deprecated and will be removed in a future release.
• fcommon
  Determines whether the compiler treats common symbols as global definitions.
• fextend-arguments, Qextend-arguments
  Controls how scalar integer arguments are extended in calls to unprototyped and varargs functions.
• fkeep-static-consts, Qkeep-static-consts
  Tells the compiler to preserve allocation of variables that are not referenced in the source.
• fmath-errno
  Tells the compiler that errno can be reliably tested after calls to standard math library functions.
• fminshared
  Specifies that a compilation unit is a component of a main program and should not be linked as part of a shareable object.
• fmudflap
  The compiler instruments risky pointer operations to prevent buffer overflows and invalid heap use. This is a deprecated option. There is no replacement option. You can consider using the Pointer Checker options (such as option -check-pointers).
• fpack-struct
  Specifies that structure members should be packed together.
• fpascal-strings
  Tells the compiler to allow for Pascal-style string literals.
• fpic
  Determines whether the compiler generates position-independent code.
• fpie
  Tells the compiler to generate position-independent code. The generated code can only be linked into executables.
• freg-struct-return
  Tells the compiler to return struct and union values in registers when possible.
• fstack-protector
  Enables or disables stack overflow security checks for certain (or all) routines.
• fstack-security-check
  Determines whether the compiler generates code that detects some buffer overruns.
• fvisibility
  Specifies the default visibility for global symbols or the visibility for symbols in a file.
• fvisibility-inlines-hidden
  Causes inline member functions (those defined in the class declaration) to be marked hidden.
• fzero-initialized-in-bss, Qzero-initialized-in-bss
  Determines whether the compiler places in the DATA section any variables explicitly initialized with zeros.
• GA
  Enables faster access to certain thread-local storage (TLS) variables.
• Gs
  Lets you control the threshold at which the stack checking routine is called or not called.
• GS
  Determines whether the compiler generates code that detects some buffer overruns.
• GT
  Enables fiber-safe thread-local storage of data.
• homeparams
  Tells the compiler to store parameters passed in registers to the stack.
• malign-double
  Determines whether double, long double, and long long types are naturally aligned. This option is equivalent to specifying option align.
• malign-mac68k
  Aligns structure fields on 2-byte boundaries (m68k compatible).
• malign-natural
  Aligns larger types on natural size-based boundaries (overrides ABI).
• malign-power
  Aligns based on ABI-specified alignment rules.
• mcmodel
  Tells the compiler to use a specific memory model to generate code and store data.
• mdynamic-no-pic
  Generates code that is not position-independent but has position-independent external references.
• mlong-double
  Lets you override the default configuration of the long double data type.
• no-bss-init, Qnobss-init
  Tells the compiler to place in the DATA section any uninitialized variables and explicitly zero-initialized variables. This option is deprecated and will be removed in a future release.
• noBool
  Disables the bool keyword.
• Qlong-double
  Changes the default size of the long double data type.
• Qsfalign
  Specifies stack alignment for functions. This option is deprecated and will be removed in a future release.