I$Open modified by Lothan

Lothan — Fri, 27 Jun 2014 23:20:11 -0000

Open Path
Opens a path to an existing file or device as specified by the pathlist

OS9 I$Open 103F 84

Entry Conditions

A access mode (D S PE PW PR E W R)

X address of the pathlist

Exit Conditions

A path number

X address of the last byte of the pathlist + 1; skips any trailing blanks

Error Output

CC carry set on error

B error code, if any

Additional Information

NitrOS-9 searches for the file in one of the following:
- The directory specified by the pathlist if the pathlist begins with a slash.
- The working data directory, if the pathlist does not begin with a slash.
- The working execution directory, if the pathlist does not begin with a slash and if the execution bit is set in the access mode.
NitrOS-9 returns a path number for later system calls to use to identify the file.
The access mode parameter lets you specify which read and/or write operations are to be permitted. When set, each access mode bit enables one of the following: Write, Read, Read and Write, Update, Directory I/O.
The access mode must conform to the access permission attributes associated with the file or device. (See the Create system call.) Only the owner can access a file unless the appropriate public permission bits are set.
The update mode might be slightly slower than the others because it might require pre-reading of sectors for random access of bytes within sectors.
Several processes (users) can open files at the same time. Each device has an attribute that specifies whether or not it is shareable.
If the single-user bit is set, the file opened for singer-user access regardless of the settings of the file’s permission bits.
You must open directory files for read or write if the directory bit (Bit 7) is set in the access mode.
Open Path always uses the lowest path number available for the process.

Recent changes to I$Open