Hi
Please find the example to user file open in kernel below. source file #linux/
sound/sound_firmware.cstruct file* filp;
filp = filp_open(fn, 0, 0);
if (IS_ERR(filp))
{
printk(KERN_INFO "Unable to load '%s'.\n", fn);
return 0;
}
IS_ERR expand to below example.
#define IS_ERR_VALUE(x) unlikely((x) >= (unsigned long)-MAX_ERRNO)
static inline long __must_check IS_ERR(__force const void *ptr)
{
return IS_ERR_VALUE((unsigned long)ptr);
}
-Anand Moon
On Thursday, November 7, 2013 11:24 AM, 乃宏周 <naive231@gmail.com> wrote:
In kernel source,
`IS_ERR_VALUE` is defined:
#define IS_ERR_VALUE(x) unlikely((x) >= (unsigned long)-MAX_ERRNO)
It's usage can be realized literally, but definition is not.
Can I use this macro to determines the kernel API's result is valid?
Example:
if (IS_ERR_VALUE(filp_open(device)))
{
filp_close(device);
}
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