This reference documents version 1.0.8 of the C API.
sprintf()-like string.
sscanf().
MPDM_2MBS - Creates a multibyte string value from a wide char string.
mpdm_t MPDM_2MBS(wchar_t * wcs);
| wcs | the wide char string |
Creates a multibyte string value from the wcs wide char string,
converting it by mpdm_wcstombs(). Take note that multibyte string values
are not properly strings, so they cannot be used for string comparison
and such.
MPDM_A - Creates an array value.
mpdm_t MPDM_A(int n);
| n | Number of elements |
Creates a new array value with n elements.
MPDM_ENS - Creates a string value from an external string, with size.
mpdm_t MPDM_ENS(wchar_t * wcs, int s);
| wcs | the external wide character string |
| s | the size in chars the string will hold |
Creates a new string value with size s. The wcs string must be
a dynamic value (i.e. allocated by malloc()) that will be freed on
destruction.
MPDM_F - Creates a file value.
mpdm_t MPDM_F(FILE * f);
| f | the file descriptor |
Creates a new file value.
MPDM_H - Creates a hash value.
mpdm_t MPDM_H(int n);
| n | Number of buckets in the hash (0: use default) |
Creates a new hash value with n buckets. The number of buckets must be a prime number. If n is 0, an optimal number of buckets will be used.
MPDM_I - Creates an integer value.
mpdm_t MPDM_I(int i);
| i | the integer |
Creates a new integer value. MPDM integers are strings.
MPDM_IS_ARRAY - Tests if a value is an array.
int MPDM_IS_ARRAY(mpdm_t v);
| v | the value |
Returns non-zero if v is an array.
MPDM_IS_EXEC - Tests if a value is executable.
int MPDM_IS_EXEC(mpdm_t v);
| v | the value |
Returns non-zero if v is executable.
MPDM_IS_HASH - Tests if a value is a hash.
int MPDM_IS_HASH(mpdm_t v);
| v | the value |
Returns non-zero if v is a hash.
MPDM_IS_STRING - Tests if a value is a string.
int MPDM_IS_STRING(mpdm_t v);
| v | the value |
Returns non-zero if v is a string.
MPDM_LS - Creates a string value from a literal string.
mpdm_t MPDM_LS(wchar_t * wcs);
| wcs | the wide character string |
Creates a new string value from a literal, wide character string. A pointer to the string will be stored in the value (not a copy).
MPDM_MBS - Creates a string value from a multibyte string.
mpdm_t MPDM_MBS(char * mbs);
| mbs | the multibyte string |
Creates a new string value from a multibyte string, that will be
converted to wcs by mpdm_mbstowcs().
MPDM_NMBS - Creates a string value from a multibyte string, with size.
mpdm_t MPDM_NMBS(char * mbs, int s);
| mbs | the multibyte string |
| s | the size |
Creates a new string value with the first s characters from the mbs
multibyte string, that will be converted to wcs by mpdm_mbstowcs().
MPDM_NS - Creates a string value from a string, with size.
mpdm_t MPDM_NS(wchar_t * wcs, int s);
| wcs | the wide character string |
| s | the size in chars the string will hold |
Creates a new string value with a copy of the first s characters from the wcs string.
MPDM_R - Creates a real value.
mpdm_t MPDM_R(double r);
| r | the real number |
Creates a new real value. MPDM integers are strings.
MPDM_S - Creates a string value from a string.
mpdm_t MPDM_S(wchar_t * wcs);
| wcs | the wide character string |
Creates a new string value from a wide character string. The value will store a copy of the string that will be freed on destruction.
MPDM_X - Creates a new executable value.
mpdm_t MPDM_X(mpdm_t (* func)(mpdm_t args));
| func | the C code function |
Creates a new executable value given a pointer to the func C code function. The function must receive an mpdm_t array value (that will hold their arguments) and return another one.
mpdm_adel - Deletes an element of an array.
mpdm_t mpdm_adel(mpdm_t a, int offset);
| a | the array |
| offset | subscript of the element to be deleted |
Deletes the element at offset of the a array. The array is shrinked by one. If offset is negative, is counted from the end of the array (so a value of -1 means delete the last element of the array).
Returns the deleted element.
mpdm_aget - Gets an element of an array.
mpdm_t mpdm_aget(const mpdm_t a, int offset);
| a | the array |
| offset | the subscript of the element |
Returns the element at offset of the array a.
mpdm_app_dir - Returns the applications directory.
mpdm_t mpdm_app_dir(void);
Returns a system-dependent directory where the applications store their private data, as components or resources.
mpdm_aset - Sets the value of an array's element.
mpdm_t mpdm_aset(mpdm_t a, mpdm_t e, int offset);
| a | the array |
| e | the element to be assigned |
| offset | the subscript of the element |
Sets the element of the array a at offset to be the e value. Returns the previous element.
mpdm_bseek - Seeks a value in an array (binary).
int mpdm_bseek(const mpdm_t a, const mpdm_t k, int step, int *pos);
| a | the ordered array |
| k | the key |
| step | number of elements to step |
| pos | the position where the element should be, if it's not found |
Seeks the value k in the a array in increments of step. The array should be sorted to work correctly. A complete search should use a step of 1.
If the element is found, returns the offset of the element as a positive number; otherwise, -1 is returned and the position where the element should be is stored in pos. You can set pos to NULL if you don't mind.
mpdm_bseek_s - Seeks a value in an array (binary, string version).
int mpdm_bseek_s(const mpdm_t a, const wchar_t * k, int step, int *pos);
| a | the ordered array |
| k | the key |
| step | number of elements to step |
| pos | the position where the element should be, if it's not found |
Seeks the value k in the a array in increments of step. The array should be sorted to work correctly. A complete search should use a step of 1.
If the element is found, returns the offset of the element as a positive number; otherwise, -1 is returned and the position where the element should be is stored in pos. You can set pos to NULL if you don't mind.
mpdm_chdir - Changes the working directory
int mpdm_chdir(const mpdm_t dir);
| dir | the new path |
Changes the working directory
mpdm_chmod - Changes a file's permissions.
int mpdm_chmod(const mpdm_t filename, mpdm_t perms);
| filename | the file name |
| perms | permissions (element 2 from mpdm_stat())
|
Changes the permissions for a file.
mpdm_chown - Changes a file's owner.
int mpdm_chown(const mpdm_t filename, mpdm_t uid, mpdm_t gid);
| filename | the file name |
| uid | user id (element 4 from mpdm_stat())
|
| gid | group id (element 5 from mpdm_stat())
|
Changes the owner and group id's for a file.
mpdm_clone - Creates a clone of a value.
mpdm_t mpdm_clone(const mpdm_t v);
| v | the value |
Creates a clone of a value. If the value is multiple, a new value will be created containing clones of all its elements; otherwise, the same unchanged value is returned.
mpdm_close - Closes a file descriptor.
mpdm_t mpdm_close(mpdm_t fd);
| fd | the value containing the file descriptor |
Closes the file descriptor.
mpdm_cmp - Compares two values.
int mpdm_cmp(const mpdm_t v1, const mpdm_t v2);
| v1 | the first value |
| v2 | the second value |
Compares two values. If both has the MPDM_STRING flag set,
a comparison using wcscmp() is returned; if both are arrays,
the size is compared first and, if they have the same number
elements, each one is compared; otherwise, a simple pointer
comparison is done.
mpdm_collapse - Collapses an array.
mpdm_t mpdm_collapse(mpdm_t a, int offset, int num);
| a | the array |
| offset | deletion offset |
| num | number of elements to collapse |
Collapses an array value, deleting num elements at the specified offset.
mpdm_dump - Dumps a value to stdin.
void mpdm_dump(const mpdm_t v);
| v | The value |
Dumps a value to stdin. The value can be complex. This function is for debugging purposes only.
mpdm_dump_unref - Dumps all unreferenced values.
void mpdm_dump_unref(void);
Dumps all unreferenced values.
mpdm_dumper - Returns a visual representation of a complex value.
mpdm_t mpdm_dumper(const mpdm_t v);
| v | The value |
Returns a visual representation of a complex value.
mpdm_encoding - Sets the current charset encoding for files.
int mpdm_encoding(mpdm_t charset);
| charset | the charset name. |
Sets the current charset encoding for files. Future opened files will be assumed to be encoded with charset, which can be any of the supported charset names (utf-8, iso-8859-1, etc.), and converted on each read / write. If charset is NULL, it is reverted to default charset conversion (i.e. the one defined in the locale).
This function stores the charset value into the ENCODING item
of the mpdm_root() hash.
Returns a negative number if charset is unsupported, or zero if no errors were found.
mpdm_exec - Executes an executable value.
mpdm_t mpdm_exec(mpdm_t c, mpdm_t args);
| c | the code value |
| args | the arguments |
Executes an executable value. If c is a scalar value, its data should be a pointer to a directly executable C function with a prototype of mpdm_t func(mpdm_t args); if it's a multiple one, the first value's data should be a pointer to a directly executable C function with a prototype of mpdm_t func(mpdm_t b, mpdm_t args) and the second value will be passed as the b argument. This value is used to store bytecode or so when implementing virtual machines or compilers.
Returns the return value of the code. If c is NULL or not executable, returns NULL.
mpdm_exists - Tests if a key exists.
int mpdm_exists(const mpdm_t h, const mpdm_t k);
| h | the hash |
| k | the key |
Returns 1 if k is defined in h, or 0 othersize.
mpdm_expand - Expands an array.
mpdm_t mpdm_expand(mpdm_t a, int offset, int num);
| a | the array |
| offset | insertion offset |
| num | number of elements to insert |
Expands an array value, inserting num elements (initialized to NULL) at the specified offset.
mpdm_gettext - Translates a string to the current language.
mpdm_t mpdm_gettext(const mpdm_t str);
| str | the string |
Translates the str string to the current language.
This function can still be used even if there is no real gettext
support() by manually filling the I18N hash.
If the string is found in the current table, the translation is returned; otherwise, the same str value is returned.
mpdm_gettext_domain - Sets domain and data directory for translations.
int mpdm_gettext_domain(const mpdm_t dom, const mpdm_t data);
| dom | the domain (application name) |
| data | directory contaning the .mo files |
Sets the domain (application name) and translation data for translating
strings that will be returned by mpdm_gettext().data must point to a
directory containing the .mo (compiled .po) files.
If there is no gettext support, returns 0, or 1 otherwise.
mpdm_glob - Executes a file globbing.
mpdm_t mpdm_glob(const mpdm_t spec, const mpdm_t base);
| spec | Globbing spec |
| base | Optional base directory |
Executes a file globbing. spec is system-dependent, but usually
the * and ? metacharacters work everywhere. base can contain a
directory; if that's the case, the output strings will include it.
In any case, each returned value will be suitable for a call to
mpdm_open().
Returns an array of files that match the globbing (can be an empty array if no file matches), or NULL if globbing is unsupported.
mpdm_hdel - Deletes a key from a hash.
mpdm_t mpdm_hdel(mpdm_t h, const mpdm_t k);
| h | the hash |
| k | the key |
Deletes the key k from the hash h. Returns the previous value, or NULL if the key was not defined.
mpdm_hget - Gets a value from a hash.
mpdm_t mpdm_hget(const mpdm_t h, const mpdm_t k);
| h | the hash |
| k | the key |
Gets the value from the hash h having k as key, or NULL if the key does not exist.
mpdm_hget_s - Gets the value from a hash (string version).
mpdm_t mpdm_hget_s(const mpdm_t h, const wchar_t * k);
| h | the hash |
| k | the key |
Gets the value from the hash h having k as key, or NULL if the key does not exist.
mpdm_home_dir - Returns the home user directory.
mpdm_t mpdm_home_dir(void);
Returns a system-dependent directory where the user can write documents and create subdirectories.
mpdm_hset - Sets a value in a hash.
mpdm_t mpdm_hset(mpdm_t h, mpdm_t k, mpdm_t v);
| h | the hash |
| k | the key |
| v | the value |
Sets the value v to the key k in the hash h. Returns the previous value of the key, or NULL if the key was previously undefined.
mpdm_hset_s - Sets a value in a hash (string version).
mpdm_t mpdm_hset_s(mpdm_t h, const wchar_t * k, mpdm_t v);
| h | the hash |
| k | the key |
| v | the value |
Sets the value v to the key k in the hash h. Returns the previous value of the key, or NULL if the key was previously undefined.
mpdm_hsize - Returns the number of pairs of a hash.
int mpdm_hsize(const mpdm_t h);
| h | the hash |
Returns the number of key-value pairs of a hash.
mpdm_ins - Insert an element in an array.
mpdm_t mpdm_ins(mpdm_t a, mpdm_t e, int offset);
| a | the array |
| e | the element to be inserted |
| offset | subscript where the element is going to be inserted |
Inserts the e value in the a array at offset. Further elements are pushed up, so the array increases its size by one. Returns the inserted element.
mpdm_ival - Returns a value's data as an integer.
int mpdm_ival(mpdm_t v);
| v | the value |
Returns a value's data as an integer. If the value is a string, it's converted via sscanf and returned; non-string values have all an ival of 0. The converted integer is cached, so costly string conversions are only done once. Values created with the MPDM_IVAL flag set have its ival cached from the beginning.
mpdm_join - Joins all elements of an array into one.
mpdm_t mpdm_join(const mpdm_t s, const mpdm_t a);
| s | joiner string |
| a | array to be joined |
Joins all elements from a into one string, using s as a glue.
mpdm_keys - Returns the keys of a hash.
mpdm_t mpdm_keys(const mpdm_t h);
| h | the hash |
Returns an array containing all the keys of the h hash.
mpdm_new - Creates a new value.
mpdm_t mpdm_new(int flags, const void *data, int size);
| flags | flags |
| data | pointer to real data |
| size | size of data |
Creates a new value. flags is an or-ed set of flags, data is a pointer to the data the value will store and size the size of these data (if value is to be a multiple one, size is a number of elements, or a number of bytes otherwise).
This function is normally not directly used; use any of the type creation macros instead.
mpdm_open - Opens a file.
mpdm_t mpdm_open(const mpdm_t filename, const mpdm_t mode);
| filename | the file name |
| mode | an fopen-like mode string |
Opens a file. If filename can be open in the specified mode, an mpdm_t value will be returned containing the file descriptor, or NULL otherwise.
If the file is open for reading, some charset detection methods are
used. If any of them is successful, its name is stored in the
DETECTED_ENCODING element of the mpdm_root() hash. This value is
suitable to be copied over ENCODING or TEMP_ENCODING.
If the file is open for writing, the encoding to be used is read from
the ENCODING element of mpdm_root() and, if not set, from the
TEMP_ENCODING one. The latter will always be deleted afterwards.
mpdm_pclose - Closes a pipe.
mpdm_t mpdm_pclose(mpdm_t fd);
| fd | the value containing the file descriptor |
Closes a pipe.
mpdm_pop - Pops a value from an array.
mpdm_t mpdm_pop(mpdm_t a);
| a | the array |
Pops a value from the array (i.e. deletes from the end and returns it).
mpdm_popen - Opens a pipe.
mpdm_t mpdm_popen(const mpdm_t prg, const mpdm_t mode);
| prg | the program to pipe |
| mode | an fopen-like mode string |
Opens a pipe to a program. If prg can be open in the specified mode, an mpdm_t value will be returned containing the file descriptor, or NULL otherwise.
mpdm_push - Pushes a value into an array.
mpdm_t mpdm_push(mpdm_t a, mpdm_t e);
| a | the array |
| e | the value |
Pushes a value into an array (i.e. inserts at the end).
mpdm_queue - Implements a queue in an array.
mpdm_t mpdm_queue(mpdm_t a, mpdm_t e, int size);
| a | the array |
| e | the element to be pushed |
| size | maximum size of array |
Pushes the e element into the a array. If the array already has size elements, the first (oldest) element is deleted from the queue and returned.
Returns the deleted element, or NULL if the array doesn't have size elements yet.
mpdm_read - Reads a line from a file descriptor.
mpdm_t mpdm_read(const mpdm_t fd);
| fd | the value containing the file descriptor |
Reads a line from fd. Returns the line, or NULL on EOF.
mpdm_ref - Increments the reference count of a value.
mpdm_t mpdm_ref(mpdm_t v);
| v | the value |
Increments the reference count of a value.
mpdm_regex - Matches a regular expression.
mpdm_t mpdm_regex(mpdm_t r, const mpdm_t v, int offset);
| r | the regular expression |
| v | the value to be matched |
| offset | offset from the start of v->data |
Matches a regular expression against a value. Valid flags are 'i', for case-insensitive matching, 'm', to treat the string as a multiline string (i.e., one containing newline characters), so that ^ and $ match the boundaries of each line instead of the whole string, 'l', to return the last matching instead of the first one, or 'g', to match globally; in that last case, an array containing all matches is returned instead of a string scalar.
If r is a string, an ordinary regular expression matching is tried over the v string. If the matching is possible, the match result is returned, or NULL otherwise.
If r is an array (of strings), each element is tried sequentially as an individual regular expression over the v string, each one using the offset returned by the previous match. All regular expressions must match to be successful. If this is the case, an array (with the same number of arguments) is returned containing the matched strings, or NULL otherwise.
If r is NULL, the result of the previous regex matching is returned as a two element array. The first element will contain the character offset of the matching and the second the number of characters matched. If the previous regex was unsuccessful, NULL is returned.
mpdm_root - Returns the root hash.
mpdm_t mpdm_root(void);
Returns the root hash. This hash is stored internally and can be used as a kind of global symbol table.
mpdm_rval - Returns a value's data as a real number (double).
double mpdm_rval(mpdm_t v);
| v | the value |
Returns a value's data as a real number (double float). If the value is a string, it's converted via sscanf and returned; non-string values have all an rval of 0. The converted double is cached, so costly string conversions are only done once. Values created with the MPDM_RVAL flag set have its rval cached from the beginning.
mpdm_seek - Seeks a value in an array (sequential).
int mpdm_seek(const mpdm_t a, const mpdm_t k, int step);
| a | the array |
| k | the key |
| step | number of elements to step |
Seeks sequentially the value k in the a array in increments of step. A complete search should use a step of 1. Returns the offset of the element if found, or -1 otherwise.
mpdm_seek_s - Seeks a value in an array (sequential, string version).
int mpdm_seek_s(const mpdm_t a, const wchar_t * k, int step);
| a | the array |
| k | the key |
| step | number of elements to step |
Seeks sequentially the value k in the a array in increments of step. A complete search should use a step of 1. Returns the offset of the element if found, or -1 otherwise.
mpdm_shift - Extracts the first element of an array.
mpdm_t mpdm_shift(mpdm_t a);
| a | the array |
Extracts the first element of the array. The array is shrinked by one.
Returns the deleted element.
mpdm_shutdown - Shuts down MPDM.
void mpdm_shutdown(void);
Shuts down MPDM. No MPDM functions should be used from now on.
mpdm_size - Returns the size of an element.
int mpdm_size(const mpdm_t v);
| v | the element |
Returns the size of an element.
mpdm_sort - Sorts an array.
mpdm_t mpdm_sort(const mpdm_t a, int step);
| a | the array |
| step | increment step |
Sorts the array. step is the number of elements to group together.
Returns the sorted array (the original one is left untouched).
mpdm_sort_cb - Sorts an array with a special sorting function.
mpdm_t mpdm_sort_cb(const mpdm_t a, int step, mpdm_t cb);
| a | the array |
| step | increment step |
| asort_cb | sorting function |
Sorts the array. step is the number of elements to group together. For each pair of elements being sorted, the executable mpdm_t value sort_cb is called with an array containing the two elements as argument. It must return a signed numerical mpdm_t value indicating the sorting order.
Returns the sorted array (the original one is left untouched).
mpdm_splice - Creates a new string value from another.
mpdm_t mpdm_splice(const mpdm_t v, const mpdm_t i, int offset, int del);
| v | the original value |
| i | the value to be inserted |
| offset | offset where the substring is to be inserted |
| del | number of characters to delete |
Creates a new string value from v, deleting del chars at offset and substituting them by i. If del is 0, no deletion is done. both offset and del can be negative; if this is the case, it's assumed as counting from the end of v. If v is NULL, i will become the new string, and both offset and del will be ignored. If v is not NULL and i is, no insertion process is done (only deletion, if applicable).
Returns a two element array, with the new string in the first element and the deleted string in the second (with a NULL value if del is 0).
mpdm_split - Separates a string into an array of pieces.
mpdm_t mpdm_split(const mpdm_t s, const mpdm_t v);
| s | the separator |
| v | the value to be separated |
Separates the v string value into an array of pieces, using s as a separator.
If the separator is NULL, the string is splitted by characters.
If the string does not contain the separator, an array holding the complete string is returned.
mpdm_sprintf - Formats a sprintf()-like string.
mpdm_t mpdm_sprintf(const mpdm_t fmt, const mpdm_t args);
| fmt | the string format |
| args | an array of values |
Formats a string using the sprintf() format taking the values from args.
mpdm_sregex - Matches and substitutes a regular expression.
mpdm_t mpdm_sregex(mpdm_t r, const mpdm_t v, const mpdm_t s, int offset);
| r | the regular expression |
| v | the value to be matched |
| s | the substitution string, hash or code |
| offset | offset from the start of v->data |
Matches a regular expression against a value, and substitutes the found substring with s. Valid flags are 'i', for case-insensitive matching, and 'g', for global replacements (all ocurrences in v will be replaced, instead of just the first found one).
If s is executable, it's executed with the matched part as the only argument and its return value is used as the substitution string.
If s is a hash, the matched string is used as a key to it and its value used as the substitution. If this value itself is executable, it's executed with the matched string as its only argument and its return value used as the substitution.
If r is NULL, returns the number of substitutions made in the
previous call to mpdm_sregex() (can be zero if none was done).
The global variables mpdm_regex_offset and mpdm_regex_size are set to the offset of the matched string and the size of the replaced string, respectively.
Returns the modified string, or the original one if no substitutions were done.
mpdm_sscanf - Extracts data like sscanf().
mpdm_t mpdm_sscanf(const mpdm_t fmt, const mpdm_t str, int offset);
| fmt | the string format |
| str | the string to be parsed |
| offset | the character offset to start scanning |
Extracts data from a string using a special format pattern, very
much like the scanf() series of functions in the C library. Apart
from the standard percent-sign-commands (s, u, d, i, f, x,
n, [, with optional size and * to ignore), it implements S,
to match a string of characters upto what follows in the format
string. Also, the [ set of characters can include other % formats.
Returns an array with the extracted values. If n is used, the position in the scanned string is returned as the value.
mpdm_startup - Initializes MPDM.
int mpdm_startup(void);
Initializes the Minimum Profit Data Manager. Returns 0 if everything went OK.
mpdm_stat - Gives status from a file.
mpdm_t mpdm_stat(const mpdm_t filename);
| filename | file name to get the status from |
Returns a 14 element array of the status (permissions, onwer, etc.) from the desired filename, or NULL if the file cannot be accessed. (man 2 stat).
The values are: 0, device number of filesystem; 1, inode number; 2, file mode; 3, number of hard links to the file; 4, uid; 5, gid; 6, device identifier; 7, total size of file in bytes; 8, atime; 9, mtime; 10, ctime; 11, preferred block size for system I/O; 12, number of blocks allocated and 13, canonicalized file name. Not all elements have necesarily meaningful values, as most are system-dependent.
mpdm_strcat - Concatenates two strings.
mpdm_t mpdm_strcat(const mpdm_t s1, const mpdm_t s2);
| s1 | the first string |
| s2 | the second string |
Returns a new string formed by the concatenation of s1 and s2.
mpdm_string - Returns a printable representation of a value.
wchar_t *mpdm_string(const mpdm_t v);
| v | the value |
Returns a printable representation of a value. For strings, it's the value data itself; for any other type, a conversion to string is returned instead. This value should be used immediately, as it can be a pointer to a static buffer.
mpdm_sweep - Sweeps unreferenced values.
void mpdm_sweep(int count);
| count | number of values to be swept |
Destroys values with a reference count of 0. count is the
number of values to be checked for deletion; special values of
count are -1, that forces a check of all currently known values
(can be time-consuming) and 0, which tells mpdm_sweep() to check a
small group of them on each call.
mpdm_ulc - Converts a string to uppercase or lowecase.
mpdm_t mpdm_ulc(const mpdm_t s, int u);
| s | the string |
| u | convert to uppercase (1) or to lowercase (0). |
Converts s to uppercase (for u == 1) or to lowercase (u == 0).
mpdm_unlink - Deletes a file.
int mpdm_unlink(const mpdm_t filename);
| filename | file name to be deleted |
Deletes a file.
mpdm_unref - Decrements the reference count of a value.
mpdm_t mpdm_unref(mpdm_t v);
| v | the value |
Decrements the reference count of a value.
mpdm_write - Writes a value into a file.
int mpdm_write(const mpdm_t fd, const mpdm_t v);
| fd | the file descriptor. |
| v | the value to be written. |
Writes the v string value into fd, using the current encoding.