glibmm: File Utilities
Various file-related classes and functions. More...
Classes | |
class | Glib::FileError |
Exception class for file-related errors. More... | |
class | Glib::DirIterator |
The iterator type of Glib::Dir. More... | |
class | Glib::Dir |
Utility class representing an open directory. More... | |
Functions | |
bool | Glib::file_test (const std::string& filename, FileTest test) |
Returns true if any of the tests in the bitfield test are true. More... | |
int | Glib::mkstemp (std::string& filename_template) |
Opens a temporary file. More... | |
int | Glib::file_open_tmp (std::string& name_used, const std::string& prefix) |
Opens a file for writing in the preferred directory for temporary files (as returned by Glib::get_tmp_dir()). More... | |
int | Glib::file_open_tmp (std::string& name_used) |
Opens a file for writing in the preferred directory for temporary files (as returned by Glib::get_tmp_dir()). More... | |
std::string | Glib::file_get_contents (const std::string& filename) |
Reads an entire file into a string, with good error checking. More... | |
Detailed Description
Various file-related classes and functions.
Enumeration Type Documentation
Values corresponding to errno codes returned from file operations on UNIX.
Values corresponding to errno
codes returned from file operations on UNIX.
Unlike errno codes, GFileError values are available on all systems, even Windows. The exact meaning of each code depends on what sort of file operation you were performing; the UNIX documentation gives more details. The following error code descriptions come from the GNU C Library manual, and are under the copyright of that manual.
It's not very portable to make detailed assumptions about exactly which errors will be returned from a given operation. Some errors don't occur on some systems, etc., sometimes there are subtle differences in when a system will report a given error, etc.
Unlike errno
codes, FileError::Code values are available on all systems, even Windows. The exact meaning of each code depends on what sort of file operation you were performing; the UNIX documentation gives more details. The following error code descriptions come from the GNU C Library manual, and are under the copyright of that manual.
It's not very portable to make detailed assumptions about exactly which errors will be returned from a given operation. Some errors don't occur on some systems, etc., sometimes there are subtle differences in when a system will report a given error, etc.
Enumerator | |
---|---|
EXISTS |
Operation not permitted; only the owner of the file (or other resource) or processes with special privileges can perform the operation.
|
IS_DIRECTORY |
File is a directory; you cannot open a directory for writing, or create or remove hard links to it.
|
ACCESS_DENIED |
Permission denied; the file permissions do not allow the attempted operation.
|
NAME_TOO_LONG |
Filename too long.
|
NO_SUCH_ENTITY |
No such file or directory.
This is a "file doesn't exist" error for ordinary files that are referenced in contexts where they are expected to already exist. This is a "file doesn't exist" error for ordinary files that are referenced in contexts where they are expected to already exist. |
NOT_DIRECTORY |
A file that isn't a directory was specified when a directory is required.
|
NO_SUCH_DEVICE |
No such device or address.
The system tried to use the device represented by a file you specified, and it couldn't find the device. This can mean that the device file was installed incorrectly, or that the physical device is missing or not correctly attached to the computer. The system tried to use the device represented by a file you specified, and it couldn't find the device. This can mean that the device file was installed incorrectly, or that the physical device is missing or not correctly attached to the computer. |
NOT_DEVICE |
The underlying file system of the specified file does not support memory mapping.
|
READONLY_FILESYSTEM |
The directory containing the new link can't be modified because it's on a read-only file system.
|
TEXT_FILE_BUSY |
Text file busy.
|
FAULTY_ADDRESS |
You passed in a pointer to bad memory.
(GLib won't reliably return this, don't pass in pointers to bad memory.). (Glib won't reliably return this, don't pass in pointers to bad memory.) |
SYMLINK_LOOP |
Too many levels of symbolic links were encountered in looking up a file name.
This often indicates a cycle of symbolic links. This often indicates a cycle of symbolic links. |
NO_SPACE_LEFT |
No space left on device; write operation on a file failed because the disk is full.
|
NOT_ENOUGH_MEMORY |
No memory available.
The system cannot allocate more virtual memory because its capacity is full. The system cannot allocate more virtual memory because its capacity is full. |
TOO_MANY_OPEN_FILES |
The current process has too many files open and can't open any more.
Duplicate descriptors do count toward this limit. Duplicate descriptors do count toward this limit. |
FILE_TABLE_OVERFLOW |
There are too many distinct file openings in the entire system.
|
BAD_FILE_DESCRIPTOR |
Bad file descriptor; for example, I/O on a descriptor that has been closed or reading from a descriptor open only for writing (or vice versa).
|
INVALID_ARGUMENT |
Invalid argument.
This is used to indicate various kinds of problems with passing the wrong argument to a library function. This is used to indicate various kinds of problems with passing the wrong argument to a library function. |
BROKEN_PIPE |
Broken pipe; there is no process reading from the other end of a pipe.
Every library function that returns this error code also generates a 'SIGPIPE' signal; this signal terminates the program if not handled or blocked. Thus, your program will never actually see this code unless it has handled or blocked 'SIGPIPE'. Every library function that returns this error code also generates a |
TRYAGAIN |
Resource temporarily unavailable; the call might work if you try again later.
We used TRYAGAIN instead of TRY_AGAIN, because that is a defined as a macro by a Unix header. |
INTERRUPTED |
Interrupted function call; an asynchronous signal occurred and prevented completion of the call.
When this happens, you should try the call again. When this happens, you should try the call again. |
IO_ERROR |
Input/output error; usually used for physical read or write errors.
i.e. the disk or other physical device hardware is returning errors. I.e. the disk or other physical device hardware is returning errors. |
NOT_OWNER |
Operation not permitted; only the owner of the file (or other resource) or processes with special privileges can perform the operation.
|
NOSYS |
Function not implemented; this indicates that the system is missing some functionality. |
FAILED |
Does not correspond to a UNIX error code; this is the standard "failed for unspecified reason" error code present in all Error error code enumerations. Does not correspond to a UNIX error code; this is the standard "failed for unspecified reason" error code present in all Glib::Error error code enumerations. Returned if no specific code applies. |
Function Documentation
std::string Glib::file_get_contents | ( | const std::string & | filename | ) |
Reads an entire file into a string, with good error checking.
- Parameters
-
filename A file to read contents from.
- Returns
- The file contents.
- Exceptions
-
Glib::FileError
int Glib::file_open_tmp | ( | std::string & | name_used, |
const std::string & | prefix | ||
) |
Opens a file for writing in the preferred directory for temporary files (as returned by Glib::get_tmp_dir()).
prefix should a basename template; it'll be suffixed by 6 characters in order to form a unique filename. No directory components are allowed.
The actual name used is returned in name_used.
- Parameters
-
prefix Template for file name, basename only.
- Return values
-
name_used The actual name used.
- Returns
- A file handle (as from
open()
) to the file opened for reading and writing. The file is opened in binary mode on platforms where there is a difference. The file handle should be closed withclose()
.
- Exceptions
-
Glib::FileError
int Glib::file_open_tmp | ( | std::string & | name_used | ) |
Opens a file for writing in the preferred directory for temporary files (as returned by Glib::get_tmp_dir()).
This function works like file_open_tmp(std::string&, const std::string&) but uses a default basename prefix.
- Return values
-
name_used The actual name used.
- Returns
- A file handle (as from
open()
) to the file opened for reading and writing. The file is opened in binary mode on platforms where there is a difference. The file handle should be closed withclose()
.
- Exceptions
-
Glib::FileError
bool Glib::file_test | ( | const std::string & | filename, |
FileTest | test | ||
) |
Returns true
if any of the tests in the bitfield test are true.
For example, (Glib::FILE_TEST_EXISTS | Glib::FILE_TEST_IS_DIR)
will return true
if the file exists; the check whether it's a directory doesn't matter since the existence test is true. With the current set of available tests, there's no point passing in more than one test at a time.
Apart from Glib::FILE_TEST_IS_SYMLINK
all tests follow symbolic links, so for a symbolic link to a regular file file_test() will return true
for both Glib::FILE_TEST_IS_SYMLINK
and Glib::FILE_TEST_IS_REGULAR
.
- Note
- For a dangling symbolic link file_test() will return
true
forGlib::FILE_TEST_IS_SYMLINK
andfalse
for all other flags.
- Parameters
-
filename A filename to test. test Bitfield of Glib::FileTest flags.
- Returns
- Whether a test was true.
int Glib::mkstemp | ( | std::string & | filename_template | ) |
Opens a temporary file.
See the mkstemp() documentation on most UNIX-like systems. This is a portability wrapper, which simply calls mkstemp() on systems that have it, and implements it in GLib otherwise.
- Parameters
-
filename_template A string that should match the rules for mkstemp(), i.e. end in "XXXXXX"
. TheX
string will be modified to form the name of a file that didn't exist.
- Returns
- A file handle (as from open()) to the file opened for reading and writing. The file is opened in binary mode on platforms where there is a difference. The file handle should be closed with close(). In case of errors,
-1
is returned.