ef_expand_file(Interactive Command-line Input Library Fuef_expand_file(3TECLA)NAME
ef_expand_file, del_ExpandFile, ef_last_error, ef_list_expansions,
new_ExpandFile - expand filename and wildcard expressions
SYNOPSIS
cc [ flag... ] file... -ltecla [ library... ]
#include <libtecla.h>
ExpandFile *ef_expand_file(void);
ExpandFile *del_ExpandFile(ExpandFile *ef);
FileExpansion *ef_last_error(ExpandFile *ef, const char *path, int
pathlen);
int ef_list_expansions(FileExpansion *result, FILE *fp, int
term_width);
const char *new_ExpandFile(ExpandFile *ef);
DESCRIPTION
The ef_expand_file() function is part of the libtecla(3LIB) library. It
expands a specified filename, converting ~user/ and ~/ expressions at
the start of the filename to the corresponding home directories,
replacing $envvar with the value of the corresponding environment vari‐
able, and then, if there are any wildcards, matching these against
existing filenames. Backslashes in the input filename are interpreted
as escaping any special meanings of the characters that follow them.
Only backslashes that are themselves preceded by backslashes are pre‐
served in the expanded filename.
In the presence of wildcards, the returned list of filenames includes
only the names of existing files which match the wildcards. Otherwise,
the original filename is returned after expansion of tilde and dollar
expressions, and the result is not checked against existing files. This
mimics the file-globbing behavior of the UNIX tcsh shell.
The supported wildcards and their meanings are:
* Match any sequence of zero or more characters.
? Match any single character.
[chars] Match any single character that appears in chars. If chars
contains an expression of the form a-b, then any character
between a and b, including a and b, matches. The '-' character
loses its special meaning as a range specifier when it appears
at the start of the sequence of characters. The ']' character
also looses its significance as the terminator of the range
expression if it appears immediately after the opening '[', at
which point it is treated one of the characters of the range.
If you want both '-' and ']' to be part of the range, the '-'
should come first and the ']' second.
[^chars] The same as [chars] except that it matches any single charac‐
ter that does not appear in chars.
Note that wildcards never match the initial dot in filenames that start
with '.'. The initial '.' must be explicitly specified in the filename.
This again mimics the globbing behavior of most UNIX shells, and its
rational is based in the fact that in UNIX, files with names that start
with '.' are usually hidden configuration files, which are not listed
by default by the ls(1) command.
The new_ExpandFile() function creates the resources used by the
ef_expand_file() function. In particular, it maintains the memory that
is used to record the array of matching file names that is returned by
ef_expand_file(). This array is expanded as needed, so there is no
builtin limit to the number of files that can be matched.
The del_ExpandFile() function deletes the resources that were returned
by a previous call to new_ExpandFile(). It always returns NULL (that
is, a deleted object). It does nothing if the ef argument is NULL.
The ef_expand_file() function performs filename expansion. Its first
argument is a resource object returned by new_ExpandFile(). A pointer
to the start of the filename to be matched is passed by the path argu‐
ment. This must be a normal null-terminated string, but unless a length
of -1 is passed in pathlen, only the first pathlen characters will be
used in the filename expansion. If the length is specified as -1, the
whole of the string will be expanded. A container of the following type
is returned by ef_expand_file().
typedef struct {
int exists; /* True if the files in files[] exist */
int nfile; /* The number of files in files[] */
char **files; /* An array of 'nfile' filenames. */
} FileExpansion;
The ef_expand_file() function returns a pointer to a container whose
contents are the results of the expansion. If there were no wildcards
in the filename, the nfile member will be 1, and the exists member
should be queried if it is important to know if the expanded file cur‐
rently exists. If there were wild cards, then the contained files[]
array will contain the names of the nfile existing files that matched
the wild-carded filename, and the exists member will have the value 1.
Note that the returned container belongs to the specified ef object,
and its contents will change on each call, so if you need to retain the
results of more than one call to ef_expand_file(), you should either
make a private copy of the returned results, or create multiple file-
expansion resource objects with multiple calls to new_ExpandFile().
On error, NULL is returned, and an explanation of the error can be
determined by calling ef_last_error(ef).
The ef_last_error() function returns the message which describes the
error that occurred on the last call to ef_expand_file(), for the given
(ExpandFile *ef) resource object.
The ef_list_expansions() function provides a convenient way to list the
filename expansions returned by ef_expand_file(). Like the ls utility,
it arranges the filenames into equal width columns, each column having
the width of the largest file. The number of columns used is thus
determined by the length of the longest filename, and the specified
terminal width. Beware that filenames that are longer than the speci‐
fied terminal width are printed without being truncated, so output
longer than the specified terminal width can occur. The list is written
to the stdio stream specified by the fp argument.
Thread Safety
It is safe to use the facilities of this module in multiple threads,
provided that each thread uses a separately allocated ExpandFile
object. In other words, if two threads want to do file expansion, they
should each call new_ExpandFile() to allocate their own file-expansion
objects.
EXAMPLES
Example 1: Use of file expansion function.
The following is a complete example of how to use the file expansion
function.
#include <stdio.h>
#include <libtecla.h>
int main(int argc, char *argv[])
{
ExpandFile *ef; /* The expansion resource object */
char *filename; /* The filename being expanded */
FileExpansion *expn; /* The results of the expansion */
int i;
ef = new_ExpandFile();
if(!ef)
return 1;
for(arg = *(argv++); arg; arg = *(argv++)) {
if((expn = ef_expand_file(ef, arg, -1)) == NULL) {
fprintf(stderr, "Error expanding %s (%s).\n", arg,
ef_last_error(ef));
} else {
printf("%s matches the following files:\n", arg);
for(i=0; i<expn->nfile; i++)
printf(" %s\n", expn->files[i]);
}
}
ef = del_ExpandFile(ef);
return 0;
}
ATTRIBUTES
See attributes(5) for descriptions of the following attributes:
┌─────────────────────────────┬─────────────────────────────┐
│ ATTRIBUTE TYPE │ ATTRIBUTE VALUE │
├─────────────────────────────┼─────────────────────────────┤
│Interface Stability │Evolving │
├─────────────────────────────┼─────────────────────────────┤
│MT-Level │MT-Safe │
└─────────────────────────────┴─────────────────────────────┘
SEE ALSOcpl_complete_word(3TECLA), gl_get_line(3TECLA), libtecla(3LIB),
pca_lookup_file(3TECLA), attributes(5)SunOS 5.10 1 Jun 2004 ef_expand_file(3TECLA)
