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__attribute__((nonnull)) function attribute

This function attribute specifies function parameters that are not supposed to be null pointers. This enables the compiler to generate a warning on encountering such a parameter.

Note

This function attribute is a GNU compiler extension that the ARM compiler supports.

Syntax

__attribute__((nonnull(arg-index, ...)))

Where arg-index, ... denotes the argument index list.

If no argument index list is specified, all pointer arguments are marked as nonnull.

Example

The following declarations are equivalent:

void * my_memcpy (void *dest, const void *src, size_t len) __attribute__((nonnull (1, 2)));

void * my_memcpy (void *dest, const void *src, size_t len) __attribute__((nonnull));