Technical Reference: Kernel and Subsystems, Volume 1

fp_open Kernel Service

Purpose

Opens special and regular files or directories.

Syntax

#include <sys/types.h>
#include <sys/errno.h>

int fp_open (path, oflags, cmode, ext, segflag, fpp) char * path; unsigned oflags; unsigned cmode; int ext; unsigned segflag; struct file ** fpp;

Parameters

path	Points to the file name of the file to be opened.
oflags	Specifies open mode flags as described in the open subroutine.
cmode	Specifies the mode (permissions) value to be given to the file if the file is to be created.
ext	Specifies an extension argument required by some device drivers. Individual drivers determine its content, form, and use.
segflag	Specifies the flag indicating where the pointer specified by the path parameter is located: SYS_ADSPACE The pointer specified by the path parameter is stored in kernel memory. USER_ADSPACE The pointer specified by the path parameter is stored in application memory.
fpp	Points to the location where the file structure pointer is to be returned by the fp_open service.

Description

The fp_open kernel service provides a common service used by:

The file system for the implementation of the open subroutine
Kernel routines outside the file system that must open files

Execution Environment

The fp_open kernel service can be called from the process environment only.

Return Values

0	Indicates a successful operation.

Also, the fpp parameter points to an open file structure that is valid for use with the other Logical File System services. If an error occurs, one of the values from the /usr/include/sys/errno.h file is returned. The discussion of the open subroutine contains possible errno values.

Related Information

The open subroutine.

Logical File System Kernel Services in AIX 5L Version 5.2 Kernel Extensions and Device Support Programming Concepts.