---
name: "gfs_pio_open"
section: "3"
platform: "linux"
package: "libgfarm-dev"
version: "2.7.20+dfsg-1.2+b1"
release: "Debian 13 (Trixie)"
platforms: ["linux"]
url: "https://new.carta.tech/gfs_pio_open"
---

# gfs\_pio\_open(3)

open a file in the Gfarm file system

## NAME

gfs\_pio\_open - open a file in the Gfarm file system

## SYNOPSIS

```
#include <gfarm/gfarm.h>
```

**gfarm\_error\_t gfs\_pio\_open(const char \*** *gfarm\_url***, int** *flags***, GFS\_File \*** *gfp***);**

## DESCRIPTION

**gfs\_pio\_open()** opens a file in the Gfarm file system specified by *gfarm\_url*, and returns a *GFS\_File* structure to the address pointed by *gfp*. *gfarm\_url* is a path name in the Gfarm file system, or a Gfarm URL in the form of gfarm://metaserver:port/path/name.

Values of *flags* are constructed by a bitwise-inclusive-OR of the following list. Exactly one of the first three values should be specified:

**GFARM\_FILE\_RDONLY**

Open for reading only.

**GFARM\_FILE\_WRONLY**

Open for writing only.

**GFARM\_FILE\_RDWR**

Open for reading and writing.

**GFARM\_FILE\_TRUNC**

If the file already exist and is a regular file, it will be truncated to length 0 if the open mode allows writing.

**GFARM\_FILE\_APPEND**

The file is opened in append mode.

**GFARM\_FILE\_UNBUFFERED**

The file is accessed without buffering.

## RETURN VALUES

**GFARM\_ERR\_NO\_ERROR**

The function terminated successfully.

**GFARM\_ERR\_IS\_A\_DIRECTORY**

*gfarm\_url* refers to a directory.

**GFARM\_ERR\_IS\_A\_SYMBOLIC\_LINK**

*gfarm\_url* refers to a symbolic link.

**GFARM\_ERR\_OPERATION\_NOT\_PERMITTED**

*gfarm\_url* refers to not a regular file.

**GFARM\_ERR\_NO\_SUCH\_OBJECT**

A component used as a directory in *gfarm\_url* does not exist.

**GFARM\_ERR\_NOT\_A\_DIRECTORY**

A component used as a directory in *gfarm\_url* is not, in fact, a directory.

**GFARM\_ERR\_PERMISSION\_DENIED**

The requested access to the file is not allowed, or one of the directories in *gfarm\_url* did not allow search (execute) permission. Or, the authentication to the metadata server fails.

**GFARM\_ERR\_NO\_MEMORY**

Insufficient memory was available.

**GFARM\_ERR\_INVALID\_ARGUMENT**

*flags* is not valid.

**GFARM\_ERR\_GFARM\_URL\_HOST\_IS\_MISSING**

*gfarm\_url* does not include a metadata server.

**GFARM\_ERR\_GFARM\_URL\_PORT\_IS\_MISSING**

*gfarm\_url* does not include a port number of the metadata server.

**GFARM\_ERR\_UNKNOWN\_HOST**

The metadata server cannot be resolved.

**GFARM\_ERR\_TOO\_MANY\_OPEN\_FILES**

The process opens too many files.

**GFARM\_ERR\_TOO\_MANY\_OPEN\_FILES\_IN\_SYSTEM**

The system limit on the total number of open files has been reached.

**GFARM\_ERR\_NETWORK\_IS\_UNREACHABLE**

Network is unrechable.

**GFARM\_ERR\_OPERATION\_TIMED\_OUT**

Connetion timeout occurs.

**GFARM\_ERR\_PROTOCOL**

Protocol error occurs.

**GFARM\_ERR\_BROKEN\_PIPE**

Connection to the metadata server is broken.

**GFARM\_ERR\_PROTOCOL\_NOT\_SUPPORTED**

Specified authentication protocol is not supported.

**GFARM\_ERR\_AUTHENTICATION**

User authentication failed when connecting to the metadata server.

Others

An error except the above occurred. The reason is shown by **gfarm\_error\_string**(3).

## SEE ALSO

[**gfs\_pio\_close**(3)](/gfs_pio_close/3.md), [**gfs\_pio\_create**(3)](/gfs_pio_create/3.md), [**gfs\_pio\_eof**(3)](/gfs_pio_eof/3.md), [**gfs\_pio\_error**(3)](/gfs_pio_error/3.md), [**gfs\_pio\_flush**(3)](/gfs_pio_flush/3.md), [**gfs\_pio\_getc**(3)](/gfs_pio_getc/3.md), [**gfs\_pio\_getline**(3)](/gfs_pio_getline/3.md), [**gfs\_pio\_open**(3)](/gfs_pio_open/3.md), [**gfs\_pio\_putc**(3)](/gfs_pio_putc/3.md), [**gfs\_pio\_putline**(3)](/gfs_pio_putline/3.md), [**gfs\_pio\_puts**(3)](/gfs_pio_puts/3.md), [**gfs\_pio\_read**(3)](/gfs_pio_read/3.md), [**gfs\_pio\_seek**(3)](/gfs_pio_seek/3.md), [**gfs\_pio\_ungetc**(3)](/gfs_pio_ungetc/3.md), [**gfs\_pio\_write**(3)](/gfs_pio_write/3.md)