Open System Services System Calls Reference Manual (G06.25+, H06.03+)

System Functions (f - i) fcntl(2)

F_GETFD Gets the value of the ﬁle descriptor ﬂags, deﬁned in the fcntl.h header ﬁle, that

are associated with the value of the ﬁledes parameter. File descriptor ﬂags are

associated with a single ﬁle descriptor and do not affect other ﬁle descriptors that

refer to the same ﬁle. The argument1 parameter or argument2 parameter is

ignored.

The value F_GETFD is invalid for an OSSTTY or Telserv terminal device. If

this value is used in a call that speciﬁes such a device for the ﬁledes parameter,

the call fails and errno is set to [EINVAL].

F_SETFD Sets the value of the ﬁle descriptor ﬂags, deﬁned in the fcntl.h header ﬁle, that

are associated with the ﬁledes parameter to the value of the argument1 parame-

ter.

If the FD_CLOEXEC ﬂag in the argument1 parameter is 0 (zero), the ﬁle

remains open across calls to any function in the exec, tdm_exec, and

tdm_spawn sets of functions; otherwise, the ﬁle is closed on successful execu-

tion of the next function in an exec, tdm_exec,ortdm_spawn function set.

When the FD_CLOEXEC ﬂag is set, no other ﬂag can be set in the call.

The value F_SETFD is invalid for an OSSTTY or Telserv terminal device. If

this value is used in a call that speciﬁes such a device for the ﬁledes parameter,

the call fails and errno is set to [EINVAL].

F_GETFL Gets the ﬁle status ﬂags and ﬁle access modes, deﬁned in the fcntl.h header ﬁle,

for the ﬁle referred to by the ﬁledes parameter.

The ﬁle access modes can be extracted by using the mask O_ACCMODE on the

return value. File status ﬂags and ﬁle access modes are associated with the ﬁle

descriptor and do not affect other ﬁle descriptors that refer to the same ﬁle with

different open ﬁle descriptors.

The argument1 or argument2 parameter is ignored.

The O_APPEND, O_NONBLOCK, and O_SYNC ﬂags are not returned as set

if they were ignored in a previous call using F_SETFL.

F_SETFL Sets the ﬁle status ﬂags O_APPEND, O_NONBLOCK, and O_SYNC for the

ﬁle to which the ﬁledes parameter refers, from the corresponding bits in the argu-

ment1 parameter. Some ﬂags are ignored, depending on the ﬁle type, as listed:

Table 3−1. Ignored File Status Flags

File type Ignored ﬁle status ﬂags

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O_APPEND, O_NONBLOCK,

O_SYNC