ioctl question

[raymond.meyer%rambler.ru@localhost]

Does anyone know why on 64-bit NetBSD sparc64 the following code works:

ioctl(fd, SNDCTL_DSP_CHANNELS, &channels);

but the following code returns -1 from ioctl

unsigned long dsp_ch = SNDCTL_DSP_CHANNELS;
ioctl(fd, dsp_ch, &channels)

/usr/include/soundcard.h has:

#define SNDCTL_DSP_CHANNELS             _IOWR('P', 6, int)