The __ptr64 type qualifier (C only)
The keyword __ptr64 is a qualifier that can be applied to a pointer type to
constrain its size to 64 bits. When you need to switch addressing mode (AMODE) between programs,
this language extension enables the handling of a 64-bit pointer by an AMODE 31 function without
dereferencing it, for example, passing it as a parameter or receiving it as a return value.
Note: The
__ptr64 qualifier
can be used only when the METAL compiler option is specified.The
__ptr64 keyword can be used only
to qualify a pointer type. For example, int *__ptr64 p; /* 64-bit pointer */
int *r; /* 32-bit pointer, default to the model's size */
int *__ptr64 const q; /* 64-bit const pointer */
int *__far __ptr64 s; /* 64-bit far pointer */
For further information on the METAL compiler option, see z/OS XL C/C++ User's Guide. For further information on AMODE switching, see z/OS Metal C Programming Guide and Reference.