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MAGIC(3) BSD Library Functions Manual MAGIC(3)
NAME
magic_open, magic_close, magic_error, magic_file,
magic_buffer, magic_setflags, magic_check, magic_compile,
magic_load -- Magic number recognition library.
LIBRARY
Magic Number Recognition Library (libmagic, -lmagic)
SYNOPSIS
#include <magic.h>
magic_t
magic_open(int flags);
void
magic_close(magic_t cookie);
const char *
magic_error(magic_t cookie);
int
magic_errno(magic_t cookie);
const char *
magic_file(magic_t cookie, const char *filename);
const char *
magic_buffer(magic_t cookie, const void *buffer, size_t length);
int
magic_setflags(magic_t cookie, int flags);
int
magic_check(magic_t cookie, const char *filename);
int
magic_compile(magic_t cookie, const char *filename);
int
magic_load(magic_t cookie, const char *filename);
DESCRIPTION
These functions operate on the magic database file which
is described in magic(5).
The function magic_open() creates a magic cookie pointer
and returns it. It returns NULL if there was an error
allocating the magic cookie. The flags argument specifies
how the other magic functions should behave:
MAGIC_NONE No special handling.
MAGIC_DEBUG Print debugging messages to stderr.
MAGIC_SYMLINK If the file queried is a symlink, follow
it.
MAGIC_COMPRESS If the file is compressed, unpack it and
look at the contents.
MAGIC_DEVICES If the file is a block or character spe-
cial device, then open the device and try
to look in its contents.
MAGIC_MIME_TYPE
Return a MIME type string, instead of a
textual description.
MAGIC_MIME_ENCODING
Return a MIME encoding, instead of a tex-
tual description.
MAGIC_CONTINUE Return all matches, not just the first.
MAGIC_CHECK Check the magic database for consistency
and print warnings to stderr.
MAGIC_PRESERVE_ATIME
On systems that support utime(2) or
utimes(2), attempt to preserve the access
time of files analyzed.
MAGIC_RAW Don't translate unprintable characters to
a \ooo octal representation.
MAGIC_ERROR Treat operating system errors while trying
to open files and follow symlinks as real
errors, instead of printing them in the
magic buffer.
MAGIC_NO_CHECK_APPTYPE
Check for EMX application type (only on
EMX).
MAGIC_NO_CHECK_ASCII
Check for various types of ascii files.
MAGIC_NO_CHECK_COMPRESS
Don't look for, or inside compressed
files.
MAGIC_NO_CHECK_ELF
Don't print elf details.
MAGIC_NO_CHECK_FORTRAN
Don't look for fortran sequences inside
ascii files.
MAGIC_NO_CHECK_SOFT
Don't consult magic files.
MAGIC_NO_CHECK_TAR
Don't examine tar files.
MAGIC_NO_CHECK_TOKENS
Don't look for known tokens inside ascii
files.
MAGIC_NO_CHECK_TROFF
Don't look for troff sequences inside
ascii files.
The magic_close() function closes the magic(5) database
and deallocates any resources used.
The magic_error() function returns a textual explanation
of the last error, or NULL if there was no error.
The magic_errno() function returns the last operating sys-
tem error number (errno(2)) that was encountered by a sys-
tem call.
The magic_file() function returns a textual description of
the contents of the filename argument, or NULL if an error
occurred. If the filename is NULL, then stdin is used.
The magic_buffer() function returns a textual description
of the contents of the buffer argument with length bytes
size.
The magic_setflags() function sets the flags described
above. Note that using both MIME flags together can also
return extra information on the charset.
The magic_check() function can be used to check the valid-
ity of entries in the colon separated database files
passed in as filename, or NULL for the default database.
It returns 0 on success and -1 on failure.
The magic_compile() function can be used to compile the
the colon separated list of database files passed in as
filename, or NULL for the default database. It returns 0
on success and -1 on failure. The compiled files created
are named from the basename(1) of each file argument with
``.mgc'' appended to it.
The magic_load() function must be used to load the the
colon separated list of database files passed in as
filename, or NULL for the default database file before any
magic queries can performed.
The default database file is named by the MAGIC environ-
ment variable. If that variable is not set, the default
database file name is c:/progra~1/file/share/misc/magic.
magic_load() adds ``.mgc'' to the database filename as
appropriate.
RETURN VALUES
The function magic_open() returns a magic cookie on suc-
cess and NULL on failure setting errno to an appropriate
value. It will set errno to EINVAL if an unsupported value
for flags was given. The magic_load(), magic_compile(),
and magic_check() functions return 0 on success and -1 on
failure. The magic_file(), and magic_buffer() functions
return a string on success and NULL on failure. The
magic_error() function returns a textual description of
the errors of the above functions, or NULL if there was no
error. Finally, magic_setflags() returns -1 on systems
that don't support utime(2), or utimes(2) when
MAGIC_PRESERVE_ATIME is set.
FILES
c:/progra~1/file/share/misc/magic The non-compiled
default magic data-
base.
c:/progra~1/file/share/misc/magic.mgc The compiled
default magic data-
base.
SEE ALSO
file(1), magic(5)
AUTHORS
M<>ns Rullg<6C>rd Initial libmagic implementation, and config-
uration. Christos Zoulas API cleanup, error code and
allocation handling.
BSD October 6, 2008 BSD