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out32(), outbe32(), outle32()
Write a 32-bit value to a port

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out32(), outbe32(), outle32()

QNX SDP8.0C Library ReferenceAPIDeveloper

Write a 32-bit value to a port

Synopsis:

#include <hw/inout.h>

void out32( uintptr_t port, 
            uint32_t val );

#define outbe16( port,
                 val ) ...

#define outle32( port,
                 val ) ...

Arguments:

port: The port you want to write the value to.
val: The value that you want to write.

Library:

libc

Use the -l c option to qcc to link against this library. This library is usually included automatically.

Description:

The out32() function writes the 32-bit value, specified by val, to the specified port.

The outbe32() and outle32() macros write the native-endian 32-bit value, specified by val, to the specified port in big-endian or little-endian format, respectively.

Note:

The in*() and out*() functions are for accessing legacy devices on x86_64 systems that still use legacy I/O-addressed I/O ports, and should not be used in any other context.

The process must have the PROCMGR_AID_IO ability enabled, and the calling thread must have I/O privileges, or else it will fault with a SIGSEGV; see procmgr_ability(), and the ThreadCtl() _NTO_TCTL_IO_LEVEL command.

Classification:


Safety:
Cancellation point	No
Signal handler	Yes
Thread	Yes

Caveats:

Both outbe16() and outle16() are implemented as macros.

Page updated: August 11, 2025