Example

First a small example. The output is approximately that of "ls [a-c]*.c".

#include <stdio.h>
#include <stdlib.h>
#include <wordexp.h>

int
main(int argc, char **argv)
{
    wordexp_t p;
    char **w;
    int i;

    wordexp("[a-c]*.c", &p, 0);
    w = p.we_wordv;
    for (i=0; i < p.we_wordc; i++)
        printf("%s\n", w[i]);
    wordfree(&p);
    exit(EXIT_SUCCESS);
}

The string argument

Since the expansion is the same as the expansion by the shell (see sh(1)) of the parameters to a command, the string s must not contain characters that would be illegal in shell command parameters. In particular, there must not be any non-escaped newline or |, &, ;, <, >, (, ), {, } characters outside a command substitution or parameter substitution context.

If the argument s contains a word that starts with an unquoted comment character #, then it is unspecified whether that word and all following words are ignored, or the # is treated as a non-comment character.

The expansion

The expansion done consists of the following stages: tilde expansion (replacing ~user by user's home directory), variable substitution (replacing $FOO by the value of the environment variable FOO), command substitution (replacing $(command) or `command` by the output of command), arithmetic expansion, field splitting, wildcard expansion, quote removal.

The result of expansion of special parameters ($@, $*, $#, $?, $−, $$, $!, $0) is unspecified.

Field splitting is done using the environment variable $IFS. If it is not set, the field separators are space, tab and newline.

The output array

The array we_wordv contains the words found, followed by a NULL.

The flags argument

The flag argument is a bitwise inclusive OR of the following values: