LIBQCOW(3) Library Functions Manual LIBQCOW(3) # [NAME](#NAME) `libqcow.h` — Library to access the QEMU Copy-On-Write (QCOW) image file format # [SYNOPSIS](#SYNOPSIS) `#include ` Support functions ``` const char * libqcow_get_version( void); ``` ``` int libqcow_get_access_flags_read( void); ``` ``` int libqcow_get_access_flags_read_write( void); ``` ``` int libqcow_get_access_flags_write( void); ``` ``` int libqcow_get_codepage( int *codepage, libqcow_error_t **error); ``` ``` int libqcow_set_codepage( int codepage, libqcow_error_t **error); ``` ``` int libqcow_check_file_signature( const char *filename, libqcow_error_t **error); ``` Available when compiled with wide character string support: ``` int libqcow_check_file_signature_wide( const wchar_t *filename, libqcow_error_t **error); ``` Available when compiled with libbfio support: ``` int libqcow_check_file_signature_file_io_handle( libbfio_handle_t *bfio_handle, libqcow_error_t **error); ``` Notify functions ``` void libqcow_notify_set_verbose( int verbose); ``` ``` int libqcow_notify_set_stream( FILE *stream, libqcow_error_t **error); ``` ``` int libqcow_notify_stream_open( const char *filename, libqcow_error_t **error); ``` ``` int libqcow_notify_stream_close( libqcow_error_t **error); ``` Error functions ``` void libqcow_error_free( libqcow_error_t **error); ``` ``` int libqcow_error_fprint( libqcow_error_t *error, FILE *stream); ``` ``` int libqcow_error_sprint( libqcow_error_t *error, char *string, size_t size); ``` ``` int libqcow_error_backtrace_fprint( libqcow_error_t *error, FILE *stream); ``` ``` int libqcow_error_backtrace_sprint( libqcow_error_t *error, char *string, size_t size); ``` File functions ``` int libqcow_file_initialize( libqcow_file_t **file, libqcow_error_t **error); ``` ``` int libqcow_file_free( libqcow_file_t **file, libqcow_error_t **error); ``` ``` int libqcow_file_signal_abort( libqcow_file_t *file, libqcow_error_t **error); ``` ``` int libqcow_file_open( libqcow_file_t *file, const char *filename, int access_flags, libqcow_error_t **error); ``` ``` int libqcow_file_close( libqcow_file_t *file, libqcow_error_t **error); ``` ``` int libqcow_file_is_locked( libqcow_file_t *file, libqcow_error_t **error); ``` ``` ssize_t libqcow_file_read_buffer( libqcow_file_t *file, void *buffer, size_t buffer_size, libqcow_error_t **error); ``` ``` ssize_t libqcow_file_read_buffer_at_offset( libqcow_file_t *file, void *buffer, size_t buffer_size, off64_t offset, libqcow_error_t **error); ``` ``` off64_t libqcow_file_seek_offset( libqcow_file_t *file, off64_t offset, int whence, libqcow_error_t **error); ``` ``` int libqcow_file_get_offset( libqcow_file_t *file, off64_t *offset, libqcow_error_t **error); ``` ``` int libqcow_file_set_parent_file( libqcow_file_t *file, libqcow_file_t *parent_file, libqcow_error_t **error); ``` ``` int libqcow_file_get_format_version( libqcow_file_t *file, uint32_t *format_version, libqcow_error_t **error); ``` ``` int libqcow_file_get_encryption_method( libqcow_file_t *file, uint32_t *encryption_method, libqcow_error_t **error); ``` ``` int libqcow_file_set_keys( libqcow_file_t *file, const uint8_t *key, size_t key_size, libqcow_error_t **error); ``` ``` int libqcow_file_set_utf8_password( libqcow_file_t *file, const uint8_t *utf8_string, size_t utf8_string_length, libqcow_error_t **error); ``` ``` int libqcow_file_set_utf16_password( libqcow_file_t *file, const uint16_t *utf16_string, size_t utf16_string_length, libqcow_error_t **error); ``` ``` int libqcow_file_get_media_size( libqcow_file_t *file, size64_t *media_size, libqcow_error_t **error); ``` ``` int libqcow_file_get_utf8_backing_filename_size( libqcow_file_t *file, size_t *utf8_string_size, libqcow_error_t **error); ``` ``` int libqcow_file_get_utf8_backing_filename( libqcow_file_t *file, uint8_t *utf8_string, size_t utf8_string_size, libqcow_error_t **error); ``` ``` int libqcow_file_get_utf16_backing_filename_size( libqcow_file_t *file, size_t *utf16_string_size, libqcow_error_t **error); ``` ``` int libqcow_file_get_utf16_backing_filename( libqcow_file_t *file, uint16_t *utf16_string, size_t utf16_string_size, libqcow_error_t **error); ``` ``` int libqcow_file_get_number_of_snapshots( libqcow_file_t *file, int *number_of_snapshots, libqcow_error_t **error); ``` Available when compiled with wide character string support: ``` int libqcow_file_open_wide( libqcow_file_t *file, const wchar_t *filename, int access_flags, libqcow_error_t **error); ``` Available when compiled with libbfio support: ``` int libqcow_file_open_file_io_handle( libqcow_file_t *file, libbfio_handle_t *file_io_handle, int access_flags, libqcow_error_t **error); ``` # [DESCRIPTION](#DESCRIPTION) The [`libqcow_get_version`](#libqcow_get_version)() function is used to retrieve the library version. # [RETURN VALUES](#RETURN_VALUES) Most of the functions return NULL or -1 on error, dependent on the return type. For the actual return values see ``. # [ENVIRONMENT](#ENVIRONMENT) None # [FILES](#FILES) None # [NOTES](#NOTES) libqcow can be compiled with wide character support (wchar\_t). To compile libqcow with wide character support use: `./configure --enable-wide-character-type` or define: `_UNICODE` or `UNICODE` during compilation. `LIBQCOW_WIDE_CHARACTER_TYPE` in libqcow/features.h can be used to determine if libqcow was compiled with wide character support. # [SEE ALSO](#SEE_ALSO) `` # [AUTHORS](#AUTHORS) Joachim Metz <joachim.metz@gmail.com> # [BUGS](#BUGS) Please report bugs of any kind on the project issue tracker: https://github.com/libyal/libqcow/issues # [COPYRIGHT](#COPYRIGHT) Copyright (C) 2010-2026, Joachim Metz <joachim.metz@gmail.com>. This is free software; see the source for copying conditions. There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. June 26, 2026 Linux 4.19.0-gvisor --- Document: libqcow(3) from libqcow 20260703-r2 (Chainguard OS) Source: https://github.com/libyal/libqcow